Atsushi Nakajima/Synopsis

Armed Detective Agency vs. Port Mafia Arc
Aimless and starving, Atsushi arrives in Yokohama two weeks after being kicked out of his orphanage. Although plagued by the orphanage staff's cruel words, he refuses to submit and die. Initially reluctant, he decides to steal in order to survive. He intends on waiting for the next person to pass him by the Tsurumi River's bank, only to come across a young man drowning in the river and ends up saving him.

Quickly coming to, the man is displeased with being saved. Atsushi responds with great confusion, and the man clarifies he was trying to commit suicide by drowning. However, at the same time, he wanted his suicide to go without disturbance. As Atsushi gets entangled in his attempt, the man intends on doing something in return. He hears Atsushi's stomach growl and relates to the feeling, claiming he has not eaten in a few days himself. However, the river swept up his wallet, leaving him without money.

Soon after, Atsushi meets the man's colleague, Doppo Kunikida. Eventually, the two strangers end up treating Atsushi to chazuke in exchange for saving the suicidal man's life. The man finally properly introduces himself as Osamu Dazai. During the meal, Atsushi learns Dazai and Kunikida are detectives of the gifted Armed Detective Agency.

Atsushi learns their current investigation involves a giant white tiger that Atsushi remembers as one that has been following and taunting him lately after being kicked out. After forceful persuasion via Kunikida, he reveals the tiger was the cause of severe damage to the orphanage he was kicked out of. Now, it appears the tiger followed him all the way to Yokohama.

Using reward money as a bribe, Dazai pulls Atsushi into a plan as bait to capture the tiger once and for all. However, during their wait, an agitated Atsushi is at a loss for words when met with Dazai's complete nonchalance towards the tiger's looming threat. As moonlight pours into the abandoned building, Atsushi himself transforms into the aggressive white tiger. However, Dazai uses his ability to nullify the tiger, returning Atsushi to normal.

He wakes up in a dormitory and is called by Dazai, the one who set up his lodgings. Dazai claims he is about to die, and Atsushi quickly moves to check the scene, only to be met by yet another failed suicide attempt of Dazai's. After helping him, Atsushi meets with Kunikida as well, who informs them of a mad bomber at the Agency.

At the site, a young bomber holds one of the part-time clerks hostage and demands to see the Agency's president. Dazai and Kunikida plays rock-paper-scissors to determine who tries to diffuse the situation. After losing, Kunikida approaches the man, but he recognizes Kunikida and his ability, demanding he does as he says or else the bomb detonates. At a stalemate, Dazai makes Atsushi approach the young man to take care of the situation himself.

Terrified and nervous, Atsushi ends up going on a personal rant. He understands both he and the young man have nowhere to turn to. He also urges him to try finding work or another purpose instead of harming others because of his own misfortune. His intensity disarms the young man's defenses and Kunikida subdues him with his ability, The Matchless Poet.

Relieved, Atsushi is caught off-guard by an unseen figure pushing him, making him fall on the detonation device. Panicking, Atsushi uses his own body to lessen the bomb's impact, much to Dazai's shock. The bomb, however, does not go off. The bomber stands next to Kunikida and Dazai who both comment on Atsushi's impulsiveness.

The clerk, Naomi Tanizaki, hugs the bomber who turns out to be her older brother, Jun'ichirō Tanizaki. Confused, Atsushi questions the situation, to which Dazai reveals it to be his entrance exam for the Armed Detective Agency. The Agency's director, Yukichi Fukuzawa, arrives and confirms Atsushi passing the entrance exam, though he leaves the final decision to Dazai. Atsushi notices Naomi with the prop arm that pushed him onto the fake bomb, bewildering him with the elaborate setup of the exam. Dazai retorts that, if he declines, Atsushi has to leave the dorm with nowhere else to go, giving Atsushi no other choice but to accept the job.

At Café Uzumaki, Tanizaki profusely apologizes to Atsushi for causing him so much stress. Kunikida advises Atsushi not to ruin the Agency's name, while the Tanizaki siblings introduce themselves. Atsushi asks them what they did before joining the Agency, but Dazai suggests he guess their backgrounds.

Atsushi correctly assumes Tanizaki and Naomi to be students, while he guesses Kunikida to be a former government worker. Dazai reveals that Kunikida is a former math teacher, afterwards asking Atsushi to guess his former job. Kunikida remarks that no one knows his past job, having a monetary reward for the one who guesses it right. Amazed by the large sum, Atsushi eagerly guesses, but he ultimately fails.

Tanizaki receives a call from the Agency with a request from client. Her issue is a group of dangerous men hanging around her company's building. After the explanation, Kunikida assigns the investigation as Atsushi's first mission and orders Tanizaki to accompany him; Naomi joins them as well.

Before Atsushi and the company depart, Kunikida warns him of Ryunosuke Akutagawa and the Port Mafia. Kunikida informs him that Akutagawaa has an ability solely for murder, and the Agency cannot handle him. Thus, combat against him is strictly discouraged, admitting himself to be of no match for Akutagawa.

Led by their client Higuchi, Atsushi, Tanizaki, and Naomi later find themselves in a secluded alley. She reveals herself as a Port Mafia member, specifically Akutagawa's subordinate. She opens fire on the group, and the sight of Naomi's severe injuries brings Atsushi to his knees and at a loss for the situation.

His fear worsens after Akutagawa himself arrives, having attacked Tanizaki from behind. Akutagawa elaborates the Port Mafia's target is Atsushi himself, intending to claim an unknown third party's bounty on him alive, much to Atsushi's confusion. Akutagawa tells Atsushi that it is his fault for causing trouble to his comrades, bringing in flashbacks of his orphanage headmaster's harsh words condemning him for living.

After witnessing Akutagawa's ability Rashomon, Atsushi stumbles on the ground. Tanizaki, still conscious, urges him to run away. Instead, Atsushi's impulses drive him to narrowly avoid another attack, where he grabs Higuchi's gun to try and take Akutagawa down. Rashomon devours the bullets, making it impossible for Atsushi to defeat Akutagawa in this situation.

Rashomon severs Atsushi's right leg, causing him to relive another flashback of the headmaster's abuse. Here, the headmaster strikes and admonishes Atsushi for crying in pain, telling him no orphan abandoned by his own family has the right to cry. Although Atsushi knows that he has been abandoned and mistreated his whole life, he acknowledges that he has never given up regardless of the fact.

The tiger takes over and regenerates Atsushi's leg, impressing Akutagawa. When it appears Akutagawa kills him, it turns out to be one of Tanizaki's illusions. The real Atsushi attempts to ambush Akutagawa from behind, but Dazai arrives and nullifies both their abilities, rendering Atsushi unconscious.

Atsushi later awakens in the Agency's medical ward, with Kunikida seated beside him. After he remembers what happened, he immediately asks about Tanizaki and Naomi, Kunikida informs him that they are alright. When the two begin discussing the bounty on Atsushi, Kunikida explains that they will not waver and fight the mafia. However, Atsushi notices Kunikida's seeming anxiety and starts to feel guilty about putting the Agency in danger. After asking Atsushi to think how he can help, Kunikida leaves the room.

After hearing a distant explosion, Atsushi goes down the street and learns that it was done by the mafia's combat division, Black Lizard. He worries about what would happen if they attacked the Agency, so he calls Higuchi using her business card and tells her that he is quitting the Agency, urging them to find him alone.

He later bumps into Kunikida when he is leaving the office with his belongings, but he rushes back when he hears gunshots coming from the direction of the Agency, only to find that the detectives had utterly trounced the mafia's Black Lizard. As Kunikida complains how the raid being the "worst-case scenario" requires them to apologize to the neighbors, Atsushi begins to cry in relief realizing the Agency's true strength and that he has found a place to belong.

While Atsushi helps clean the office with the rest of the agency, he notices that Ranpo receives a ton of praise despite not helping and insulting the others. He is then asked to aid Ranpo on his next job, who states he does not need an assistant but someone to help him using the train.

The two of them later arrive at the murder scene and meet with officers Minoura and Sugimoto, the former stating they do not want their help. The victim, Minoura's subordinate Yamagiwa, was found in the river early in the morning with three bullet holes and no other evidence. Another body is caught in the police search net, but it turns out to be Dazai. Atsushi asks if Dazai was trying to commit suicide again, but he explains that he was not.

Shortly after Ranpo teases Sugimoto trying to get him to solve the case in 60 seconds, Atsushi thinks to himself that he probably looks that flustered most the time. He is also unimpressed by Ranpo's confident motto compared to his own. After Ranpo determines that Sugimoto is, in fact, the murderer using his ability Super Deduction, Dazai pushes Atsushi towards the armed officer, causing him to miss his shot. Atsushi then manages to disarm him and pin Sugimoto to the ground.

At the police station, Atsushi witnesses Sugimoto confess to the murder, explaining that he was working for a Diet member who ordered him to stop Yamagiwa from exposing his corruption. Ranpo later closes the case after Sugimoto reveals the location of the corruption evidence. Leaving the station, Dazai explains to Atsushi that Ranpo's Super Deduction is not an ability and merely solves crimes with his own intellect. Atsushi then realizes why Ranpo is never admonished despite his attitude.

In the morning, Atsushi is worried that Dazai is missing, but Kunikida, Ranpo, and Kenji Miyazawa think that he might be elsewhere like usual. To help appease his worry, Tanizaki volunteers to help him look for Dazai. Atsushi is glad to see him safe, but Tanizaki nervously relives Agency doctor Akiko Yosano's "treatment" and advises Atsushi never to get injured. Ranpo urges him to have a keen sense for danger, such as what will happen in ten seconds. Yosano arrives and sees no one else with Atsushi (which he thinks to be "danger"), so she asks him to accompany her for shopping.

After their spree, they ride the train back to the Agency, where they get embroiled in a bombing situation perpetrated by the mafia. They split up to find and diffuse the bombs, upon which he encounters a girl in kimono whom he encountered earlier. As he tells her about the situation, Atsushi is attacked by a katana-wielding phantom, which is the girl's ability. Launching a barrage of attacks on him, the girl introduces herself as Kyōka Izumi, a Port Mafia assassin whose ability receives instructions through her phone. Atsushi thinks he stands no chance against his opponent, but he decides to stand back up in order to save the passengers, believing that he can find his reason to live if he does so.

He partially transforms his arm into the tiger's limb and defends himself from Demon Snow. After dodging successive attacks, Atsushi demands the girl to deactivate her ability and tell him where the bomb is. She reveals the bomb strapped beneath her kimono, to which Atsushi berates her emotionlessness and apparent coldness. Through the PA system, Yosano tells Atsushi that the bomb has a detonator that can disarm the bomb. He asks Kyōka for it and presses it, but the bomb continues to count down.

The voice on the phone orders her to show the people the might of the Port Mafia by letting the bomb go off, so Kyōka pushes herself away from Atsushi and jumps off, saying her true emotions not wanting to kill anymore. Atsushi realizes her genuine feelings and, tapping into his ability, jumps off the train as well and rips the bomb off the girl, protecting her from its blast.

Kyōka is brought and treated to the Agency infirmary, while Atsushi is reprimanded by Kunikida for bringing in a wanted serial killer. As they ask her for information about the mafia, Kyōka asks them to treat her to tofu if they want her to provide them intel. As Atsushi ends up having his money thinned out due to Kyōka's appetite, she explains that she was taken in by the mafia after getting orphaned and used her ability for assassination missions. Moreover, they find out that the voice giving instructions through her phone is Akutagawa.

Outside, Kunikida asks Atsushi to hand her to the military police despite Atsushi's disapproval, knowing that she shall get capital punishment for killing 35 people. Kunikida also advises him not to let someone else beyond saving into his boat lest they drown together, but Atsushi wishes to give her another chance at life, just like how Dazai saved and took him in.

Atsushi accompanies Kyōka out to the streets and inadvertently tells her that they shall go on a date. He treats her to crêpe, gets her some gifts, and takes her throughout Yokohama. As Atsushi's wallet thins out, they soon arrive at their last stop – a police station – and she thanks him for his company. Atsushi worries that she will get executed if she proceeds, upon which he is suddenly impaled from behind by Akutagawa, who reveals to have tracked Kyōka's phone to kidnap the weretiger.

Atsushi wakes up inside a trafficking ship and gets confronted by Akutagawa, wondering where his hatred stems from. As the mafioso beats him up, Kyōka soon intervenes, but Akutagawa easily overwhelms her. Atsushi spots Kunikida below to rescue him, while Kyōka sets off a bomb nearby to sink the ship. Kunikida asks Atsushi to jump and leave the girl behind, but Atsushi firmly decides to give her a second chance and turns back to save her.

Before Akutagawa can kill Kyōka, Atsushi arrives to save her and urges the mafioso that they settle their matter at once. Akutagawa gets the upper hand with his strong offensive force, but Atsushi later retaliates with his ability. Akutagawa persistently attacks him and intermittently expresses his animosity towards him. Despite Rashomon's continuous attacks, Atsushi's regeneration enables him to survive, later berating Akutagawa for leading Kyōka down a dark path rather than directing her to another course. Atsushi soon defeats Akutagawa and plunges him towards the sea. As the ship sinks, Atsushi passes out, but Kyōka manages to get themselves aboard Kunikida's boat.

In the aftermath, Atsushi is glad that he and Kyōka survived, though he worries whether the Agency can forgive her 35 murders. To his surprise, he finds the Agency members playing with Kyōka and giving her treats, including Ranpo. Fukuzawa arrives to see the criminal in question, upon which Kyōka asks him to let her stay at the Agency. Atsushi also implores the President to help her out, which Fukuzawa accepts.

Minoura and his subordinate arrive at the office to ask for the Agency's help. He spots Kyōka and gets suspicious of her, causing Atsushi to improvise a story to get her out of apprehension. Fukuzawa simply tells the officer that she is his granddaughter, much to Atsushi's relief. Later, Atsushi and Kunikida learn about Kenji's rural town and their systems. Kunikida then tasks Atsushi to go with Kenji to investigate the recent explosion of a vehicle in town.

At the crime scene, Atsushi gets discouraged at the sight of the bizarre case, but Kenji tells him that they must first collect information. With Kenji's popularity throughout town, they soon set their eyes on a suspicious gang in question, from whom Kenji thinks they can extract the truth with their sincere questioning. Atsushi realizes how potentially effective his simple idea is. However, he gets terrified with the menacing gang, while Kenji straightforwardly asks for their involvement with the car explosion, which the gang denies. Kenji then accepts their answer and leaves with Atsushi.

Outside, Atsushi tries to point out their lies, but Kenji assures him that sincere communication will lead to understanding, which is a point that Atsushi acknowledges. On their way back, the gang corners them and “confesses” their involvement in the explosion after all. Kenji gladly thanks them, only for the gang to attack him from behind. As Atsushi panics, Kenji gets up unscathed and single-handedly defeats the entire gang with his monstrous strength. With the case closed, Atsushi calls Kunikida and expresses how too peculiar Kenji's methods are. Nonetheless, Kunikida explains to Atsushi what and how Kenji's ability works.

The Guild Arc
Atsushi wakes up and discovers that his roommate is Kyōka. At the office, Dazai advises him that it is his job to look after her, which Atsushi accepts. Dazai also informs them that the one who placed the bounty on Atsushi is a North American gifted organization known as the Guild. Tanizaki bursts in and tells them that the Guild has just arrived at their doorstep. Their leader, Francis Scott Key Fitzgerald, asks to purchase the Agency from Fukuzawa, an offer which the President rejects.

The following morning, the Agency are unsettled by the possible moves undertaken by the Guild, including how a mafia-affiliated building vanished overnight and how Kenji has turned missing after seeing them out the building. Kunikida tasks Atsushi and Tanizaki to search for Kenji, and Naomi accompanies them as well. As they look for Kenji along the streets, Atsushi and Tanizaki soon realize that Naomi has vanished.

They soon get transported to a different dimension along with other civilians by Lucy Maud Montgomery, an apprentice from the Guild. She shows the detectives their captured comrades and asks them to play with her ability, a gigantic doll-like creature named Anne. If they defeat her, Lucy promises to set their subordinates free. The other civilians flee from the room, leaving only Atsushi, Tanizaki, and a doctor behind in the dimension. As soon as Atsushi and Tanizaki accept her challenge, Anne instantly captures Tanizaki and imprisons him.

Atsushi dodges Anne's onslaughts with his ability until he gets his hand on the key to the prison room. However, it turns out to be a feint that even Lucy admits she does not know to use the key. Running out of ideas, Atsushi heads towards the exit to seek Dazai's help, but the doctor stops him and imparts some advice towards him on how to possibly defeat Lucy. As he earns back his resolve to save his comrades, Atsushi readies himself, but he gets caught by another Anne and dragged into the prison room.

Eventually, the doctor reveals to Lucy the truth: Tanizaki has projected an illusion of the door shutting close, while Atsushi actually resists getting dragged to the prison room with his tiger limbs. Atsushi also reveals having tied a ribbon on Lucy's waist earlier, then he pulls her towards him and demands she deactivate her ability. Otherwise, he will drag her together with him to the prison room. As Atsushi lets go, Lucy deactivates her ability and brings back the imprisoned people back to reality.

Atsushi tries to approach Lucy and apologizes to her, only for her to flee. Kyōka then arrives and embraces Atsushi out of worry. The doctor bids his farewell to Atsushi and imparts a final advice to him. As he and his young companion leave, Kyōka suddenly cowers out of fear, much to Atsushi's confusion and worry.

The next day, Atsushi hands Kyōka her first work for the Agency, which is to deliver an evidence to a court judge. As they arrive at the location, she is denied entrance, but she tries to resolve it using her own tactical strategy. Atsushi accompanies her to infilitrate the building, though she soon ends up stunning the judge himself, ending in a partial failure. Afterwards, Atsushi treats her to crêpe to cheer her up, later asking her why she still keeps her phone. She explains how it is special to her despite her wish never to activate her ability through it again. However, it suddenly rings, with a voice activating Demon Snow to attack Atsushi.

A woman, Kōyō Ozaki, arrives and tells Kyōka that she has arrived to bring her back to the mafia. Atsushi tells her that Kyōka shall never return to the mafia again, as she now belongs in the Agency. Atsushi activates his ability to attack the woman, only to be stabbed by another demon like Demon Snow, Golden Demon. She announces that she has to kill Atsushi and the rest of the Agency upon orders of mafia boss Ōgai Mori. Kyōka then agrees to come with her, though it turns out to be an act to catch Kōyō off-guard.

She snatches Kōyō's phone and activates Demon Snow to battle her opponent, as Kōyō keeps urging her to return to the mafia. She also reminds Kyōka how she is suited for killing, just like how Demon Snow killed her parents, much to Atsushi's surprise. In that moment, mafia reinforcements arrive to finish off Atsushi and retrieve Kyōka and Kōyō.

However, Kunikida and Kenji intervene and arrive to Atsushi's aid, inciting a war between the Agency and the mafia. Just then, two Guild members arrive alongside four more other members. Kōyō orders her men to open fire, though the Guild members easily overwhelm all the forces, including Atsushi and his subordinates.

Yosano later treats Atsushi and Kunikida. As Fukuzawa arrives to inquire about their conditions, Kunikida apologizes for failing to prevent the mishap, after which the President heads out. Atsushi and Dazai later converse with Kōyō in the infirmary, with whom Atsushi gets angry for causing Kyōka's disappearance. He transforms his arm into a tiger limb out of anger and tries to attack her, but Dazai quickly stops him by nullifying his ability. He then asks Atsushi to leave the matter to his hands.

When Kunikida updates Fukuzawa on the situation, he soon hears that the President may be under attack; Atsushi happens to pass by and suggests they help him at once. To appease his worry, Kunikida demonstrates to Atsushi how he knows the President can easily defeat his attackers.

Later, the Agency convenes at the Bankoudou Hall, where Dazai explains their strategy. To make up for their numbers, they shall split into various teams: one defense team and two offense teams. Atsushi is paired with Dazai as one offense team; Tanizaki is partnered with Kunikida as another offense team; and Fukuzawa, Ranpo, Yosano, and Kenji comprise the defense team. Dazai then finishes with their main objective which is to keep their base hidden as possible, after which Fukuzawa declares that they must survive the three-way ability war.

While awaiting Naomi's and Kirako Haruno's passenger train from the Guild's hitmen, Atsushi watches Dazai tease a dog with some treats which he also eats himself. Atsushi worries how the Agency can pull through the conflict, though Dazai thinks that they can turn the tide by about three hundred ways. However, he recognizes the mafia's most advantageous position compared to their least advantageous, considering Mori's logical and cunning calculations. Since the clerks have now let down their guard, Dazai reckons that Mori shall exploit such situation. Dazai's stomach later aches possibly from the dog treats he ate, leaving Atsushi behind. Atsushi turns to the dog and compliments Dazai despite his apparent strangeness.

As the train arrives, Naomi and Haruno introduce Atsushi to their acquaintance, who bumps themself on Atsushi and pulls up their sleeve to reveal various razor blades on their arm. Unbeknownst to him, Atsushi soon gets immersed in a curse, which turns out to be Q's ability. Seeing his companions turn hostile against him, Atsushi defends himself by using his tiger strength; he attacks Haruno and strangles Naomi in the process.

Dazai soon returns and asks him to come to his senses. As Atsushi grasps the situation, he realizes that he was the one cursed rather than the other way around. As Dazai ends the curse through his ability and Q departs through the train, Atsushi undergoes a breakdown, thinking how he does not deserve to live. Dazai slaps and lectures him not to pity himself, lest his life will be an unceasing nightmare. Dazai then announces that they must move onward with their counterattack.

Atsushi returns to the Agency and comes across Kōyō confined in the infirmary. He wonders how she can be confined if the door is unlocked, to which she clarifies that Dazai's locks are all abstract. She then correctly guesses that the lad may have come from having committed a blunder, where Atsushi tries to explain how he merely wished to protect his comrades. Kōyō tries to snap him out of it with discouragement; in the end, when asked where Dazai is, Atsushi tells her that he shall meet with a government official from the Special Division for Unusual Powers.

Kōyō sees how the Agency can find an invaluable ally in the Special Division, and Atsushi notices her seeming unconcern to the issue for a mafia executive. She threatens that she shall set out to divulge all intel she has just gathered, though she timidly informs him how she must remain silent after Dazai has made an unspeakable act to her. Calling it out as a jest, she explains how she and Dazai simply made a deal: she is to stay put in confinement while he tries to locate Kyōka, whom Kōyō notes is about to start a massacre. Recalling how she herself has never experienced Kyōka's wish to "live in the light", Kōyō implores Atsushi to help Kyōka.

Later, Atsushi awaits Dazai who has not yet returned, during which he is approached by Fitzgerald himself. Thinking how the war could end if he defeats Fitzgerald, Atsushi repetitively strikes him with his tiger strength, but Fitzgerald easily blocks his attacks. Finally, Fitzgerald overpowers and asks him to come with him, but Kyōka suddenly arrives. She quickly attacks Fitzgerald, eventually rescuing Atsushi as they escape from the scene.

Hiding from Fitzgerald, Kyōka tells Atsushi that she has called the police with a false report to arrive at their location and prevent the Guild from performing any rash actions. Recalling his conversation with Kōyō about Kyōka's dark tendencies, Atsushi wonders why Kyōka came back instead of remaining incognito and staying out of the war. She tells him that she belongs to the Agency and promises to fight for it, even if she needs to resort to her inner monstrosity. They soon approach the two policemen nearby to seek aid. As one of the two officers is notified that a young wanted serial killer in kimono is spotted in the area, he grows suspicious of Kyōka. She immediately slashes the officer out of stimulus, upon which Atsushi quickly stops her from attacking the second officer and grabs her to escape once again.

They soon encounter Fitzgerald and his companion, having anticipated the situation with the help of their tactician. As Atsushi and Kyōka are instantly and severely shot from above by Mark Twain, Fitzgerald grabs Atsushi and takes him to Moby Dick summoned by Herman. Amidst Kyōka's pleas not to take Atsushi away, Fitzgerald advises her that saving others does not suit her, to which she weeps and wonders why she is given hope if such were the case. Overwhelmed by his injuries, Atsushi is taken aboard the Guild's base and immediately departs.

Restrained before Fitzgerald, Atsushi is welcomed to Moby Dick, where he encounters Lucy, now demoted as a servant. Fitzgerald tells him that they are in search of a certain book and that Atsushi is the guidepost that can lead them to it. He reveals having kidnapped Atsushi to keep him from the oncoming incineration of Yokohama, specifically where the Agency and the mafia are based. To do so, Fitzgerald shows Q's doll, which makes Atsushi realize the danger of the plan.

As the doll soon begins its laughter, Atsushi tells Fitzgerald that the Agency shall cooperate in finding the Book, which piques Fitzgerald's interest. The latter agrees to establish a deal, but only with those who shall survive the incident. Fitzgerald then rips out the doll to activate the curse. Atsushi is locked up in a cell and tries to come up with a plan to help out. The orphanage director appears to him in a vision, dissuading him that he will only cause misfortune to others, just like how he dragged Kyōka and Lucy to their respective ordeals. In a fit of rage, Atsushi lashes out at the apparition and dissipates it.

Lucy passes by his cell and mocks him on her way to burn Q's mutilated doll. Atsushi asks her to set him free for everyone's sake, but Lucy declines. He then advises her to run, but she tells him how the Guild is the only thing she has left, unlike him who is blessed with his comrades. She shows her scarred arm that was caused by the painful time she had on the orphanage, to which Atsushi shows his identically scarred abdomen and thereby relates to her story as someone who also experienced the same unbearable acts in the past. Though he knows how they both experienced loneliness, Atsushi believes that leaving the people below to die is akin to abandoning their past selves.

Quickly bringing him to her dimension, Lucy tells Atsushi that there is no other way to stop the curse, but he states that Dazai's nullification ability can stop it if he touches the doll. Lucy tries to dissuade him due to the dangers that might befall him on the way down, but Atsushi remains steadfast in his plan, recalling a quote he once read in which regrets are a product of not doing anything. Lucy then decides to help him as Anne hands him a parachute, asking Atsushi to save her soon. As she promises to wait for his return, Atsushi jumps off the aircraft and agrees to come back for her.

On his way down, Atsushi's parachute is punctured by Twain's ability-aided sniping. As he prepares to accept his end, he eventually comes to terms with the white tiger, upon which he fully transforms into the creature and lands on the ground unscathed. Twain fires .50-caliber bullets at him, but Atsushi evades them. He then witnesses the various cursed citizens and spots a baby about to fall off some stairs. Atsushi taps into his tiger speed and successfully catches the crib, later handing the child to Michizō Tachihara nearby.

As Atsushi notices some strange objects lined up along the streets, Twain shoots a tanker truck in front of him and heavily injures him from the blast. Twain rains down a surge of shots at Atsushi and immobilizes him. As he tries to reach out to Q's doll, Dazai intervenes, nullifies the curse by touching the doll, and sets off a saturation chaff smokescreen that emanates from the strange objects, jamming Twain's infrared sensors and radar.

Atsushi and Dazai retreat to a nearby nook. Though they have stopped the cursed rampage, Dazai tells Atsushi that Q is still in the Guild's confinement and can launch the same attack how many times they want. He adds that the Special Division is currently frozen and cannot therefore collaborate with them. Recalling the quote he once read in a book – that the head may err but never the blood – Atsushi recommends a solution in fighting the Guild: forming an alliance with the Port Mafia. He soon opens a conversation with Fukuzawa and suggests his idea; in the end, the Agency and the mafia agree to hold a temporary ceasefire between them.

Later, as Ranpo and Dazai plan their next action after retrieving intel on Moby Dick, Dazai enlists Atsushi to perform a solo infiltration in Moby Dick. Dazai explains that he is a combat-type and high-speed ability user who has already been aboard the aircraft and would only be captured rather than killed if ever he gets caught, making him the most suitable choice for the mission. Though initially plagued with the orphanage director's discouragement to make him refuse, Atsushi accepts the task.

As Atsushi and Tanizaki head to the library, Atsushi learns that Kyōka is yet to become an official Agency member, since she has not yet passed an entrance exam. He worries that her cold-blooded nature might be an issue in assessing her suitability in the Agency. At the library, they are greeted by a government agent who directs them to the Night Crow, the Special Division's light attack helicopter. As they anxiously fly towards Moby Dick, Tanizaki activates Light Snow to hide their presence, allowing Atsushi to successfully enter the aircraft.

Atsushi finds the ship empty of its crew, only encountering Herman who tells him that everyone has fled before they crash Moby Dick to Yokohama. Atsushi urges Herman to deactivate his ability, but the latter has now lost control over it. Atsushi suggests to Dazai over the comms that they abort the mission, but Dazai asks him to stop the descent instead, which Atsushi acknowledges. After Herman directs him where the control terminal is, Atsushi asks him why he is left in the ship, to which Herman replies that the least he can do before Moby Dick crashes into Yokohama is to go down with it. As Atsushi sets out, he encounters Akutagawa along the hallway and clashes with him.

As Akutagawa is bent on killing Atsushi, who in turn does not understand the mafioso's reasoning, Dazai gives Atsushi some instructions on how to throw Akutagawa off from their path. Atsushi tosses his communicator with Dazai on the line; as Akutagawa catches it, Atsushi escapes.

Atsushi arrives at Fitzgerald's office, who turns out to be the one guarding the control terminal. Fitzgerald divulges their plan of dropping Moby Dick to Yokohama, afterwards offering him some pieces of advice to success and a chance to snatch the control terminal from him. However, Atsushi gets overwhelmed by Fitzgerald's strength, especially as he activates his ability. As Fitzgerald is about to rip off his limbs, Akutagawa arrives demanding to resume their fight, much to Atsushi's dismay. Akutagawa further chides his unfathomable attitude, given how Atsushi is quite oblivious to his strength yet is putting his life on the ship to fight.

Fitzgerald interjects and clobbers Akutagawa, while Atsushi soon tries to attack Fitzgerald while distracted. Atsushi spouts that true power lies in helping others who struggle in despair, but Fitzgerald quips that Atsushi himself is just like those people; having researched all about his past, Fitzgerald recounts one of Atsushi's violent near-death experiences in the orphanage. As the ship begins to descend, Akutagawa chuckles and escapes below together with Atsushi.

Akutagawa confronts Atsushi and spites his outlook of wanting to save others as if they can give him worth to live. The mafioso then loses interest in Atsushi, disappointed that he shall never get any sense of accomplishment from killing him. Atsushi wonders why he is hell-bent on performing such "accomplishment", to which Akutagawa spouts that only accomplishment can bring Dazai to recognize him. Before Atsushi can fully inquire, Fitzgerald finally locates them. Akutagawa engages Fitzgerald, while Atsushi flees towards a nearby elevator; Akutagawa follows him inside.

Akutagawa mockingly regrets having lost to someone worthless as him, but Atsushi retorts that he is nonetheless stronger than a mafioso who murders others just to flaunt his power. Though Atsushi sees how people respect him and recognize his strength, he adds how Akutagawa is the worthless one because of his mere desire of instilling fear on others. Akutagawa angrily grabs him and states how Atsushi is very lucky to have an outstanding ability that easily earned Dazai's acknowledgement, yet he dwells on his past and continues to turn a blind eye on everything he has. Before Atsushi can reply, they soon arrive at the ship's deck where Fitzgerald awaits.

As Akutagawa clads himself in a Rashōmon armor and battles Fitzgerald, Atsushi ponders on why Akutagawa thinks lowly of himself despite his formidable power, which Atsushi refuses to accept after all the murders he has committed out of his self-indulgence. Hence, heeding the tiger's strength, he partially transforms his limbs and joins the fight against Fitzgerald. He and Akutagawa bicker along the way, upon which Fitzgerald remarks on their similarity with each other. Offended that they are compared to each other, Atsushi and Akutagawa punch Fitzgerald.

Thinking that they have subdued Fitzgerald, Atsushi suggests they take the control terminal before they resume their clash. However, Fitzgerald resurfaces and spends all of his assets. Atsushi asks Akutagawa if he is foolish, to which Akutagawa acquiesces and tells him that his past has nothing to do with his current self. Atsushi then tells Akutagawa that he believes Dazai must have already acknowledged him long ago. Reactivating their abilities, the two charge at Fitzgerald. Initially overwhelmed by the fully-powered Fitzgerald, Atsushi and Akutagawa eventually combine their power and ultimately defeat the Guild leader who falls from Moby Dick.

They successfully stop the ship's descent, but it later continues to fall; Herman thinks that an outside party has hacked into the system. When Atsushi informs Dazai about the issue, Kyōka communicates with them from the UAV and plans to collide the aircraft to Moby Dick. Atsushi asks her to escape as well; she tells him that is unable to, hence thanking him instead and saying her goodbye upon accepting her fate. Akutagawa then grabs him to escape the ship with Herman while the UAV crashes into the airship.

Atsushi is distraught with Kyōka's fate, though Dazai and Fukuzawa arrive to tell him that Kyōka has passed her Agency entrance exam the moment she has decided to save Yokohama. As a result, the President's inhibiting ability that only works on his Agency subordinates has activated and allowed Kyōka to freely control her ability, enabling her to have Demon Snow cut off her shackles and escape in time. Atsushi then rushes to Kyōka and embraces her out of relief, while the other Agency members proudly look on to them from a distance.

Atsushi later accompanies Kyōka to the Agency office, where the Agency welcome their newest member. Kunikida later approaches him and Kyōka and scoldingly imparts them with various pieces of advice as their superior, especially not to tarnish the Agency's reputation and not to do anything they will regret. Yosano soon grabs and urges him to tell them what he truly wished to say, to which Kunikida complements them for a job well done in saving Yokohama.

Reflecting on Kunikida's advice, Atsushi asks for Kyōka's favor to call for Naomi and Haruno, to whom he apologizes for what he unintentionally did during the Q incident. The two clerks dismiss his worry and forgive him, but Tanizaki looms behind him and asks him what he did to his sister. Later, Atsushi notices that Dazai is absent in the party and wonders where he is.

In the anime, Atsushi and Akutagawa have a brief encounter at night after the Guild war. As Atsushi looks at the city skyline and musingly remarks that it is the city that they have been protecting, Akutagawa chides him for always talking nonsense.

The Guild Aftermath Arc
Following the battle with the Guild, Atsushi informs the drained Agency members about criminal organizations eyeing the Guild's alleged fortune. The next day, he and the others find Café Uzumaki ransacked and learn that the gang responsible were looking for them. They instantly locate the gang's hideout, where Atsushi and Kunikida take out the armed guards. When they return to the café, they are introduced to Lucy – the café's new waitress – who bashfully throws a metal box at Atsushi upon seeing him.

Later, Atsushi is handed by Ranpo a case and meets up with Tanizaki on an apparent traffic incident of a 40-year-old man, who is later identified as the director from Atsushi's previous orphanage. Tanizaki tries to console him, but Atsushi is quite relieved on the matter. Atsushi soon meets up with an informant on the case – who turns out to be Akutagawa – and tells him that the incident is not a murder-related case but a traffic accident.

Atsushi reads the director's file on his early life, realizes the reason he had always been locked up in the orphanage, and is told that the director might have come to Yokohama to find and praise him for his victorious feat against the Guild, greatly conflicting Atsushi. Dazai comes up to him and advises that, though his director indeed made him experience hell, it cultivated a strong will in him. He acknowledges if Atsushi does not forgive him, albeit parting ways with him by saying that people cry when their fathers pass away, to which Atsushi weeps.

Later on, Atsushi and Kunikida visit Katai Tayama to have him look into Moby Dick's control terminal that was previously hacked, but Katai confesses that he is unable to use his ability due to a feeling of unrequited love with a woman he "encountered" recently. Atsushi suggests they find the woman so Katai can confess to her, but Kunikida and Katai are against it; nonetheless, Katai seeks their help into finding the woman. The next day, Higuchi is caught spying on them amidst the ongoing ceasefire between the Agency and the mafia. To his and Kunikida's surprise, Higuchi asks to tell her everything about the woman on the photo they are looking for.

The three search for the woman, and Katai soon catches up to them. They eventually find the woman coming out of a laundromat, after which Katai and Higuchi chase her. In the end, they learn that the woman is Gin, Akutagawa's younger sister. As Katai gets rejected, Atsushi and Kunikida give him some time to recover, as Kunikida knows that he will get back to work after he resolves the turmoil in himself. Atsushi then remarks how Kunikida truly understands Katai.

While eating in his and Kyōka's dorm, she shows her distrust towards Demon Snow, which independently assists her with some work. The next day, they head to Café Uzumaki, where they are welcomed by an annoyed Lucy. After the latter voices her grudge towards Atsushi, she hands them a dispatch specifically for Kyōka, which is to deliver a briefcase to a client. As they head to a quay, they split up and search for the boat containing the briefcase. After failing to find the right boat, Lucy confronts him, reveals having stolen the page that tells where the boat is, and tosses it to the water. Atsushi reclaims it, but he gets entangled in the mooring chains, enlisting Lucy's help in the process.

As she brings the both of them to her dimension, Atsushi thanks her and admits that he searched for her in Moby Dick after all. He then suggests a way for them to dry their clothes instantly with her ability, only for it to fail and embarrass Lucy. When she kicks him out of her dimension, the two regroup with Kyōka, and they locate the boat containing the briefcase. Obtaining the document that reports on the death of Kyōka's parents, they realize that Demon Snow – which Kyōka long thought killed her parents – is actually a sign of her parents' love. Atsushi is quite inquisitive, but Lucy drags him out of the café to give Kyōka some time alone.

Atsushi and Kyōka try out Lucy's coffee, which he compliments, unlike Kyōka who finds it average. The latter further remarks that, if such coffee costs the same as the manager's, their customers will not go along with it, much to Lucy's annoyance. When Atsushi asks if anyone in the Guild made coffee, Lucy remembers Louisa often making it and describes her to be a good person to Lucy. Atsushi then thinks how they are good friends, though Lucy shyly denies it. He also finds out that Louisa has never used her ability on herself, except only when ordered to.

During the T. J. Eckleburg case, Atsushi and Ranpo are visited by Edgar Allan Poe, who seeks the great detective's help in solving the killer's identity in a case.

Cannibalism Arc
Atsushi and the rest of the Agency discover that a masked assassin has been recently attacking ability users at night, including Fukuzawa. Later, he and Kunikida search for Dazai, who had been shot by a sniper. With Dazai undergoing medical operation, Atsushi and the others think of their strategy as the mafia arrives at the hospital where the President is taken. Ranpo encourages them, especially asking Kunikida as their interim director to issue his comrades with his orders. As such, Atsushi and the rest of the Agency simultaneously guard Fukuzawa's room.

As they face off with the mafia's main forces led by Chūya, Atsushi and the others begin to dissipate, revealing it as Tanizaki's illusion. In truth, Kenji had blasted through the wall and carried the President out to safety with the others, rethinking their strategy in their escape.

Atsushi and Kunikida search for Alexander Pushkin, the suspected virus ability user, in a criminal den. When they are spotted, Atsushi taps into his tiger speed to catch up to the fleeing culprit; Pushkin shoots him, but Atsushi catches the bullet with his teeth. The two detectives soon face five armed children, whom Kunikida subtly subdues with a tear gas bomb. Feeling the oddity of the situation, Atsushi and Kunikida soon find a child strapped with grenades. Kunikida asks Atsushi to chase down Pushkin and to leave the child to him instead. Eventually, Atsushi catches and subdues Pushkin, only to discover that the man is not the actual Pushkin they are looking for.

Ranpo and Yosano regroup with Atsushi and the caught man, from whom they retrieve a file on the virus ability user, though Ranpo deems it to also be a decoy document. The fake Pushkin then relays Fyodor's message that the rules cannot be changed. Atsushi ponders whether the message means that many others will die even after the Cannibalism virus reaches its time limit.

Atsushi and the others soon fetch Kyōka and Tanizaki after escaping from the mafia. Despite their new order from Fukuzawa himself not to fight the mafia, Ranpo persuades them that it is inevitable to fight them after they tried and failed to catch the virus ability user. The Agency members agree to launch a frontal assault at the mafia, except for Atsushi and Kunikida. Ranpo then instructs him to head to Katai's and figure if the latter has any update on the Rats' hideout, after which he and the others head out.

Atsushi and later Kunikida head to Katai's apartment, where they find him missing. Kunikida smashes through the wall and retrieves a hidden camera to watch the footage. It shows Katai apparently finding the Rats' hideout, only for Fyodor to shoot him from behind. To their surprise, they uncover Katai's bloodied futon beneath them. Later, Atsushi informs Yosano and the rest that Katai has been eliminated.

Nevertheless, Katai is revealed to have been helped by Sōseki Natsume, who later intercepts Fukuzawa's and Mori's battle and urges the two leaders to flush out their mutual opponent. As a result, Dazai soon makes Atsushi and Akutagawa collaborate in catching the virus ability user, holding them down in their truck to prevent them from using their abilities. Atsushi is hesitant that Akutagawa would work together with him, but Dazai notes the mafioso's extreme concentration, almost bewildering Atsushi.

When they soon arrive at the Rats' hideout, Akutagawa tells Atsushi two reminders: that he will leave him behind or he will kill him if he needs to. After Akutagawa uses Rashōmon to enter the coal mine, Atsushi taps into his tiger speed to covertly pass through the guards undetected and enter. Despite Atsushi reminding Akutagawa that they need to work together, the mafioso ignores him, believing that he can do the task alone. Akutagawa then attacks Atsushi, planning to make it look like a casualty during the mission, but Atsushi angrily provokes him and remarks on his indiscriminate violence that must have been why Dazai discarded him years ago.

Atsushi realizes the gravity of his words and prepares for retaliation; to his surprise, Akutagawa merely shrugs it off. They are soon caught between cameras and coming patrolling guards, upon which Akutagawa captures the two guards with his ability, threatening them to work with them. One of the two then divulges about a certain room which Atsushi thinks must be the enemy's base. Since hacking is impossible, Atsushi enlists Katai's help in locating the virus ability user instead.

While waiting, Atsushi asks Akutagawa why he thinks Dazai made them pair up, but Akutagawa tells him that looking into Dazai's rationale and way of thinking will get them nowhere; rather, he simply believes in Dazai's plan. Akutagawa also asks Atsushi why he goes along with the plan, but, before he can get to the core of his answer, Katai informs them that Pushkin is two meters behind them, who turns out to be one of the two guards they have captured. He shoots Akutagawa, but Atsushi manages to push him away, merely grazing the mafioso. As Pushkin flees through a mining cart, Akutagawa prepares to chase him, only for him to weaken. To their surprise, Akutagawa has been infected with the virus.

Later, riding a minecart, Atsushi is contacted by Dazai, who advises him not to get even a slight scratch, as the virus can be acquired through open wounds. He urges them to catch Pushkin and leave Fyodor to him. Akutagawa attempts to catch Pushkin, but to no avail. As Pushkin triggers an explosion that destroys their minecart, Atsushi grabs Akutagawa and lets him ride on his back, tapping into his tiger speed. They manage to get close to Pushkin, but an earth golem emerges from the wall and intercepts. Pushkin escapes, while Atsushi and Akutagawa face Ivan Goncharov, another of Fyodor's allies.

As the two find themselves struggling against Ivan, they soon agree to work together. Atsushi turns himself as a decoy for Akutagawa to impale Ivan with Rashōmon, only for them to find out that it is a clay doll. Getting attacked by a boulder, Atsushi soon gets infected with the virus as well. With both weakened, Ivan leaves them to drown in a quicksand. Akutagawa points out there may be a way out, but he presses again why Atsushi he fights. He understands it is influenced by his past, but he does not see why Atsushi clings to a dead man's words. Atsushi claims that he is still not gone, though he admits that his appearances have decreased since the funeral. Satisfied with Atsushi's answer, Akutagawa clads him in Rashōmon, telling him that it is the way out.

Combining his and Akutagawa's powers, Atsushi finally defeats Goncharov. As Atsushi and Akutagawa head to Goncharov's base, the virus dissipates with Pushkin's defeat. However, Atsushi contacts Kunikida that Fyodor is still missing. Goncharov then blissfully implies that Fyodor is not in the hideout in the first place. However, Fyodor later gets caught by Dazai in collaboration with Fitzgerald's Eyes of God, leading to the Russian's arrest. Later, Akutagawa asks Atsushi to wait six months before he can kill him. In response, Atsushi urges him not to kill anyone within those six months, which Akutagawa honors.

In the aftermath, Atsushi and the Agency hold a banquet at a luxury liner given to them by Fitzgerald. As Atsushi approaches Dazai, the latter asks how teaming up with Akutagawa was, to which Atsushi voices how they are not compatible at all. Atsushi also tells them about their six-month deal, after which he decides to train himself with Kunikida's help in physical combat and in honing his ability.

Decay of Angels Arc
The Agency is awarded by the Ministry of Justice for their contributions in public safety one month after the events of Cannibalism. Atsushi also trains in physical combat with Kunikida, who has now been released from prison. Kunikida urges him not to let his tiger ability overpower him; he advises him that the tiger is strong, but he himself is weak. Afterwards, they head back to convene with the others.

The Agency is briefed by Kunikida on a "murder association" known as the Decay of Angels responsible for four gruesome murders of government officials, which allude to the five signs that indicate the imminent death of an "angel" in Buddhist scriptures. Fukuzawa orders them to prevent a fifth murder from happening, but Ranpo – remembering Mushitaro Oguri's warning for him not to take their next case – refuses to take the case and storms out of the office.

While reviewing the case along the streets, Atsushi is contacted by Ango and asks him to relay a warning to his comrades that there might be a spy within the government conspiring with the murder association. Afterwards, Atsushi comes across Ministry of Justice vice minister Tonan, whom Atsushi grows suspicious of after uncovering his lies during their conversation. Bearing Ango's message in mind of a possible government spy, Atsushi dodges Tonan's questions and takes his leave immediately.

Amidst the hostage situation orchestrated by Nikolai Gogol, Atsushi goes ahead of the others to the site. However, he encounters and clashes with Gogol himself, whose transfer-type ability overpowers Atsushi. He tries to stall for some time, but Atsushi is unable to hold him off after Gogol traps his leg to the ground and disappears into thin air, leaving Atsushi at the basement with no ideas of the events aboveground.

Later on, Atsushi hears the military police reinforcements arriving and asks for their help; to his shock, they are given permission to open fire at him. Kyōka and Demon Snow arrive to his aid, knocking out the soldiers unconscious. She informs him that the Agency, lured into the enemy's trap, are now wanted as criminals, making "escape" impossible for them. They head back to the crime scene and hide on the ceiling using some of Kunikida's pages he previously handed to Kyoka.

After two days, they come out of hiding, with Atsushi still in disbelief of the recent happenings. As they go incognito in the streets, Atsushi is distraught that he cannot even save the Agency that always helped him. Dazai then encourages him in a vision, making Atsushi plan on collaborating with Fitzgerald using his Eyes of God to locate Mushitaro, their sole lead who knows of the Decay of Angels. Kyōka is dubious of seeking help from a previous enemy, but Atsushi thinks of it as their only choice, just like how Fitzgerald once helped Dazai during the events of Cannibalism.

Upon arriving at their base, Atsushi spots Louisa wounded on the floor and heads straight to Fitzgerald, who is fighting a brainwashed Hawthorne. After the latter escapes, Atsushi tells Fitzgerald about the Agency's frameup, but he merely laughs at his accusation. Nevertheless, seeing Atsushi serious, Fitzgerald deems it impossible to defeat Fyodor in his confinement in Meursault, giving him every opportunity to enact his plans without interference. The Scarlet Letter suddenly tries to attack Fitzgerald at point-blank range, but the room is soon drenched in sprinkler water and dilutes the blood, courtesy of Kyōka seeing a warning to activate the sprinkler system.

The two parties then exchange terms for their deal, with Fitzgerald wishing to have the Agency doctor revive Margaret and have her kill Hawthorne. Atsushi is adamant to accept his terms with Fitzgerald's seemingly unchanged indifference, backing away from the deal. Fitzgerald then realizes Atsushi's conditions and brings them to Margaret, whose comatose condition has worsened. Seeing her status, Atsushi agrees to the deal, claiming that he cannot stand ignoring someone suffering, like how he was in his youth.

Along the way, Atsushi hears some clamor beneath the ground, upon which he and Kyōka soon find Yosano from underground after escaping. She informs Atsushi about the alleged trap, but he claims that Fitzgerald would most likely betray them after getting Margaret revived. They soon find the ambulance staff killed by a hooded figure, much to Yosano's suspicions. She then asks Atsushi and Kyōka to take Margaret to Fitzgerald and leave her to handle the mysterious figure.

Ultimately, through Eyes of God, Atsushi and Kyōka locate Mushitaro confined in a government bank. Atsushi invites Mushitaro to escape with them, though the latter declines. After Kyōka threatens him with the word "manuscript", hinting that Ranpo shall publicize his theory on Yokomizo's death, Mushitaro reluctantly agrees to go with them.

After Mushitaro spots Ango and the Special Division troops outside, he frantically decides that they must escape and avoid capture from Ango, whom he recognizes as the head of the criminal group, the Seventh Agency. Atsushi is in disbelief, but Mushitaro explains that the government made such enterprise after all. They escape from the surveillance cameras using Mushitaro's ability, much to Atsushi's awe having once stumped Ranpo. They soon find themselves nearly cornered by the troops, but Mushitaro manages to conjure a plan to escape their pursuers.

Employing a classic locked-room trick, they successfully hide from the Special Division troops and later exit the bank successfully. As they plot to steal a runaway car, Atsushi and Kyōka are hit with tranquilizing darts by Ango, who reveals how he has pinpointed their escape route using his ability. As the Special Division begin to arrive, Ango suddenly pushes the group down the sewer for them to hide and directs his men to a different direction, telling Atsushi that his role is to mislead Fyodor into thinking they are against each other.

The four leave the area by Ango's car, where he reveals that he is Dazai's middle-man while imprisoned through decoding Dazai's heart rate (that he can apparently manipulate) and that Fyodor merely made up the lie that Ango is part of the Seventh Agency. They head to Lucy's dimension after she previously marched into the Special Division headquarters defending the Agency's innocence. Atsushi, Kyōka, and Ango then ask for Mushitaro's information on the Decay of Angels.

Initially reluctant, he soon explains that the Decay of Angels is a five-man murder association headed by an "overseer". Though he does not know their end goal, he tells them of the previous steps and the step before their end goal, which is to eliminate the country using the back page of the Book within ten days. Though Lucy is worried for the Agency members, Atsushi and Kyōka are quite relieved – with Atsushi even laughing – that they simply have to steal the page within the time limit and write on it that the Agency has been framed.

In a back alley, Ango plans an infiltration mission with Atsushi, Kyōka, and Lucy, which is to halt the enemy's third stage and to retrieve the page from the enemy. Ango deems Lucy to be the heart of their strategy, with her ability vital in infiltrating the enemy without being noticed. Atsushi apologizes to Lucy for getting her involved, but Lucy shrugs it off. Per Dazai's plan, they are to head to the Sky Casino whose coin bombs shall be used by the terrorists to cause firsthand slaughters and an economic halt that might possibly cause a global economic crisis. Hence, they are to capture casino manager Sigma, a Decay of Angels member who knows the page's location; prevent the terrorism; and gain the Hunting Dogs as allies.

Upon Ango's order, Lucy transports Atsushi and Kyōka to Anne's Chamber and heads to the casino. As they arrive, they hear an explosion go off that seals all exits. Atsushi quips that they are now unable to leave and trapped with their opponents, which goes according to plan. Later, Atsushi hears the Hunting Dogs engaging in combat and heads out with Kyōka. Upon sensing fighting in the communications room way faster than they anticipated, Atsushi and Kyōka split up, with Atsushi heading to the communications room himself. At some point, Atsushi leaves a flash drive at the room containing a video revealing the truth on the Decay of Angels and their plan.

Eventually, with Sigma falling off the casino with Teruko Okura, Atsushi saves Sigma from the fall and lands atop a hanging electric box. Ango communicates with Sigma through Atsushi's phone, demanding the one who stabbed Santōka Taneda to spill the page's location, even through torture if necessary. Finally giving up, Sigma agrees to cooperate, claiming that he does not know why he was born after all. On their way down, they face Hawthorne upon them, who attacks Sigma with his blood bullet. Atsushi grapples to save Sigma before getting attacked in the forehead as well. He resists the attack and struggles to hold on to Sigma, but the latter appreciates his kindness and lets go of his hand.

Lucy soon jumps off the casino to bring him and herself to her dimension. As he thanks her, Atsushi tries to shield Lucy from Hawthorne, realizing that the latter connected a thread of blood onto him to enter the chamber. However, Anne captures Hawthorne, and Lucy imprisons him into her secret room. Lucy rejoices with capturing their enemy, but Ango tells them that they failed to retrieve the page's location and are even witnessed by the Hunting Dogs saving Sigma, a "fellow terrorist" in the government's eyes. He fearfully regrets that everything played out according to Fyodor's schemes, ending in their utter defeat.

After failing their operation, Lucy asks what they shall do from then on. Atsushi gets distraught for failing their only strategy and muses how the Agency would have solved such case if only they were together. Dazai encourages him in a vision once again, compelling Atsushi to urge his teammates to find another way. Amidst their hopelessness, Atsushi passes out. Eventually, he gains consciousness and tells them that he now knows where the page is.

As apparently passed on to him by Sigma, Atsushi reveals that the page is being held by Kamui, the Decay of Angels' boss and the mastermind behind the entire terrorism case. Though the images are rather vague, Atsushi notices a gas mask in his vision. Ango tries to come up with a way to allow the information to fully project to Atsushi's mind. As he suddenly feels Kamui's killing intent, Atsushi prompts for them to hurry and save the Agency members being targeted by Kamui.

To his relief, Atsushi is overjoyed to see Ranpo together with Kunikida, Yosano, and Katai safe from their assassinations. Atsushi runs to and embraces Kunikida, though he worries for his amputation. Kunikida dismisses his worries with Yosano's presence and with the Agency now partially complete in essence. Ranpo instructs them to search for Kenji and Tanizaki, while he sets out to negotiate with Ōchi Fukuchi. He also tells them of 10,001 Shelters – safe-setting novels prepared by Poe where he shall retreat to in case of emergency – and asks them to protect it well in case he uses one.

Atsushi and Ranpo head to Standard Island, where Atsushi sneaks into the Boswellian, a special passenger ship for VIPs, and wait for Ranpo. As the latter returns with Fukuchi, Atsushi is anxious with Ranpo's obnoxious behavior towards Fukuchi, though the latter asserts that he is fine with his attitude. Eventually, with Atsushi's curiosity towards Kamui, Ranpo brings out his glasses and deduces Kamui's identity.

With utter shock, Ranpo lights a smoke candle and instructs Atsushi to escape at all costs. Fukuchi cuts down Ranpo, who saves Atsushi from the attack and instantly retreats to Poe's safe novel. Before fully transported, Ranpo reveals Kamui to be Fukuchi and warns Atsushi of the man's ability.

Initially in disbelief, Atsushi questions Fukuchi's reasoning behind the terrorism despite being close with the President, with which Fukuchi retorts that their paths have long diverged when Fukuzawa refused to fight with him during the war. Atsushi is pressured with the gravity of his situation that shall decide the ultimate outcome of the entire incident. In spite of Ranpo's warning, Atsushi decides to face him head-on until an ally arrives.

Within a split second, Atsushi's leg is severed without him even feeling it. Regeneration instantly begins, but Fukuchi threateningly wonders if it can still grow his head back if he decapitates him, much to Atsushi's fright of fighting alone. Akutagawa intercepts the fight and makes his presence known upon Dazai's order with the rising of the smoke signal. Though visibly stressed to fight two of them, Fukuchi activates his ability and breaks the ship's handrail to use as his weapon. Akutagawa urges Atsushi to regenerate his leg within 30 seconds.

Fukuchi slices towards Akutagawa who evades his attack as told by Atsushi, which ends up cutting through the ship. Akutagawa stops his next attack with Rashōmon: Demonic Jaws, much to Atsushi's awe. As the mafioso approaches him, Fukuchi easily flips him over, similar to Fukuzawa's technique. Cornered upon a wall, Akutagawa craftily dodges his attacks until he runs out of possible moves, upon which a regenerated Atsushi saves him from Fukuchi's onslaught; they then retreat inside the ship.

Akutagawa backs away from Atsushi and angrily chides Atsushi for retreating rather than eliminating Fukuchi, to which Atsushi reminds how their opponent is on another level in terms of power. Nevertheless, Akutagawa insists on defeating Fukuchi, claiming that he does not wish to revert to something that Dazai discarded once again if he fails their mission, much to Atsushi's surprise. A ship guard tries to attack the two while distracted, though they defend themselves. Atsushi initially thinks Akutagawa will kill the man, but Akutagawa merely renders him unconscious, claiming that he still upholds his deal with Atsushi of not killing anyone within six months.

While fleeing, they plan their attack on Fukuchi, with Akutagawa plotting to use Beast Beneath the Moonlight–Rashōmon: Black Tiger's Supreme Claw, though they find loopholes in their plan, including Fukuchi's immense speed and Akutagawa's vulnerability while Rashōmon fully envelops Atsushi. Though they initially reach a deadlock on how to address the issue, they soon agree that the only way to battle Fukuchi is to fight him underwater through diverting Fukuchi's attention and attacking him from behind. As they head to get the emergency submarine, they find Fukuchi awaiting them, having seen through their tactic.

Atsushi questions Fukuchi's actions after returning from the battlefield, with which Fukuchi admits having tortured countless people upon the government's orders during war. Fukuchi reveals his grand plan of collapsing every nation to end all wars, upon which Atsushi and Akutagawa charge at him. Fukuchi's ability proves quite difficult to engage, pitting the two and attacking themselves, as well as using all possible materials as his weapons.

Despite their disadvantage, Atsushi and Akutagawa are determined to face Fukuchi, so the latter tosses his Hunting Dog blade and summons Amenogozen. Akutagawa and later Atsushi are suddenly pierced by the "space–time sword" that can blade through airspace to reach a target. As Atsushi collapses near Akutagawa, Fukuchi berates their lack of trust in each other that contributes to their loss, which Atsushi bitterly agrees with. Though Akutagawa is unfazed, Fukuchi ultimately invites him to become his apprentice as part of the Hunting Dogs and asks him to kill Atsushi for him.

Akutagawa turns a serious gaze at Atsushi and asks him to fight him amidst Atsushi's protests. In the end, their conversation is a feint, and the two exchange positions. Akutagawa quickly envelops Atsushi with Rashо̄mon, and Atsushi claws at Fukuchi for their surprise attack, severing Fukuchi's arms that leads to his death. As Atsushi acquires the page from Fukuchi, Atsushi anxiously wonders where Amenogozen was manifesting at the climactic moment. In truth, the blade cuts through the past, which then allows Fukuchi to anticipate the surprise attack and severs Atsushi's right arm, vanishing their previous victory.

Atsushi hopelessly muses how Fukuchi and his blade are unmatched and unrivaled that can defeat even Ranpo's and Dazai's strategies and cannot also be possibly compared to the world's military forces altogether, for Fukuchi can slay even defeat itself. Akutagawa immediately manifests Rashо̄mon into his shirt and cuts beneath the ship to escape with Atsushi. However, Fukuchi cuts through the past again and averts their escape, leaving Atsushi to helplessly witness Fukuchi land a fatal blow at Akutagawa. Akutagawa then bids Atsushi to escape as he cuts through the ship to have Atsushi flee through the submarine, before Akutagawa succumbs to his demise.

After Atsushi breaks out of the submarine and swims to shore, he is rescued by Ango and tells him the entire story aboard a passenger boat. Though he admits that Akutagawa sparing the guard's life ended up saving and allowing him to tell the truth of the case, Atsushi remains utterly confused on why Akutagawa let him escape. He turns to Ango for his thoughts, but Atsushi receives no response.