Chūya Nakahara/Synopsis

Fifteen Arc
Roughly fifteen years ago, Chūya's existence began as the vessel to the God known as Arahabaki. Existing as, essentially, the personification of calamity and destruction, Arahabaki knew no concept of time, though, nor personality. It simply existed, sealed away by the Japanese military. Although it had no concept beyond its own existence, Arahabaki knew something restrained and sealed it away from the outside world.

One day, Arthur Rimbaud infiltrated the military and attempted to use Arahabaki's calamitous power as a part of his ability, illumination. However, Verlaine failed, only obtaining the seal and ultimately freeing Arahabaki. Forcibly freed from its darkness-filled solitude, the shock gave a new humane existence - Chūya Nakahara. The end result made both the god and the vessel lose their memories of anything before the age of seven, eight years prior to meeting Dazai. The loss of stability made Arabahaki, now essentially merged with Chūya, lose control, decimating the facility and almost everyone in it, save Rimbaud. This, presumably, forms a valley-like street aptly dubbed Cone Street - the slums.

Although his own being with a will and personality, Chūya has no memories of his life before seven years old, the same age Arahabaki and he completely merged. He recalls the existence of Arahabaki, surrounded by blue-black darkness, sealed away in the facility, but not how Arahabaki's seal had been removed nor why he formed his own personality and being. He only recalls someone's hand pulling him from the seal and freeing him. Since then, he made finding out the truth of his origins his main priority.

At an unknown point of time, Chūya joined Sheep, a group consisting largely of teenage boys that maintained their own territory. With Chūya's Upon the Tainted Sorrow, he acted as Sheep's trump card. Although not the 'King of the Sheep', many mistake him as such because of his overwhelming power, but strictly speaking, Chūya was only a member of the council they developed. Nonetheless, he felt a strong sense of responsibility for Sheep's well-being, priding himself as their trump. Thanks to him, Sheep's reputation and turf increased as to cause issues even for the Port Mafia.

When fifteen, Sheep endured a vicious attack by Port Mafia. Chūya hunted down the Mafiosi responsible. One of the Mafiosi he tracked down, on a plane, nearly crushed to death, told him they had no choice but to retaliate. According to him, Arahabaki itself destroyed one of the Port Mafia's armories. This caught Chūya's attention, and thus he proceeds his investigation after killing the Mafiosi.

He later arrived in Suribachi City, attacking Osamu Dazai and Ryūrō Hirotsu. He demanded they inform him of the mafia's investigation of Arahabaki. He and Hirotsu end up fighting, but thanks to Dazai's No Longer Human, Chūya was defenseless. However he later gained the upper hand and freed himself - but an explosion knocked the group unconscious.

When Chūya came to, he'd been restrained by Rando, an associate executive able to conjure a hyperspace sub-region. Here, he met Ōgai Mori, Port Mafia's new boss. Mori invited him to join Port Mafia, much to Chūya's annoyance. Chūya knew Mori killed his previous boss, but the knowledge did nothing to deter Mori from his own goal of using Chūya to further the mafia's investigation of Arahabaki. To ensure Chūya complied, Mori had members of Sheep taken hostage, holding their lives over Chūya so he couldn't harm the mafia anymore, and more importantly, work alongside them. As insurance, he made him listen to a transmitter picking up Sheep members' panic and screams.

Moreover, he made Chūya and Dazai - already on ill terms with each other - work together. He forbade them from fighting each other, threatening both their lives if their investigation failed because they couldn't cooperate together. Both powerless against Mori's word, the two agreed to his terms.

During their investigations, they run into members of GSS, another group opposing the Port Mafia. Chūya succeeded in taking them down, forcing Dazai to stop shooting an already dead man, unnerved by his apathy and sadism over even the dead. They later reach Rando's residence, ransacked by GSS, here, Rando explained his own witnessing of Arahabaki.

Later, at an arcade center, Chūya and Dazai made a bet that the one who won in a fighting game would get a reward. If Chūya won, he could identify the culprit - but when Dazai won, he tried making Chūya obey his commands like a mere dog.

Members of Sheep meet Chūya in the arcade, confused and angry at his absence when their own members were in danger. They urge him not to trust Dazai, but Chūya insisted things would work out, and that the truth behind Arahabaki took priority for the sake of Sheep as well. Sheep feared Chūya betrayed them, and they risked complete elimination by their rivals without Chūya to support their defenses - Dazai used this to his advantage, telling Sheep Chūya finally found a purpose other than as their trump. Angry, the Sheep members leave.

The two return to Rando in an unused building. Chūya overheard Dazai and Rando's conversation and smashed into the room they spoke in, apprehending Rando as the culprit of the mysterious appearance of Arahabaki and the former boss. Chūya ignored Dazai's deduction of Rando's flawed account of seeing Arahabaki itself - he knew it would be impossible to accurately describe Arabahaki without having been responsible for its freedom in the first place.

He recounted his memories regarding Arahabaki, finally coming clean to Dazai and Rando of his identity. He asked if Rando had been the one that freed him and gave him form as this 'frame' for a destructive entity's existence.

In response, Rando trapped both Chūya and Dazain his ability's hyperspace, revealing an ability that even No Longer Human could not overcome on its own. As such, Chūya's ability was useless, unable to use his ability in a space that went against natural laws. Rando recounted his past, a man from Europe by the name of Arthur Rimbaud.

Eight years ago, Rimbaud infiltrated the military's base, attempting to steal Arahabaki. However, when he failed and instead found himself surrounded by military personnel. To escape, he thought of using Arahabaki as the base of his ability, Illuminations. But, trying to obtain Arahabaki, he ended up with its 'safety device', Chūya, who acted as Arahabaki's vessel before the two merged. The loss of stability freed Arahabaki, ending in the calamity that formed Cone Street.

Rimbaud succeeded in absorbing Arahabaki during the calamity, but the larger portion of the entity maintained its own individual existence as Chūya. Beyond that, Rimbaud remembered nothing of Chūya's true nature nor the truth behind the calamity. Now, he intended on killing Chūya, planning to recreate the memories of that day and unveil the truth. All for trying to recall the final moments of his friend and partner Paul Verlaine.

Chūya understood Rimbaud's reasoning, but it did not stop him from pursuing Rimbaud. He elaborated a philosophy of never removing his gloves nor used his hands in a fight. To him, he never felt the urgency of a fight nor the danger of violence, knowing his origins weren't human and thus not fully understanding the depth of such emotions as he grew up. He considered his personality and nothing more than something to keep Arahabaki's true nature stable. Not using his hands, he'd eventually fall in a fight, unable to enjoy the rush of violence nor defend himself - a means to understand and feel more attachment to his own life and humanity.

After fatally injuring Rimbaud, Chūya heard out his final wish - for Chūya to live. He assured Chūya he lived a human life already, as humans all existed as 'frames' for deeper experiences.

A month after Rimbaud's death, Chūya visited his grave, revealing that Rimbaud died with the truth of Arahabaki, and everything else of it lost in obscurity.

Sheep's member Shirase found him, apologizing before telling Chūya Sheep found a better method to protect themselves. He stabbed Chūya, revealing Sheep betrayed him, using GSS as protecting, and the knife laced with poison. Chūya managed to escape and fell into the sea.

Onshore, he and Dazai reunite. Dazai, now an official mafioso with his own squadron, received orders to kill all Sheep and GSS. However, he'd make an exception if Chūya desired. Chūya told him not to kill Sheep. Dazai agreed, ordering his squadron to carry out the plan they already decided on. Just then, Chūya realized Dazai always intended on causing the rift between Sheep and him and lost consciousness.

Sometime later, Chūya spoke to Koyo Ozaki, now his direct superior. By now he already referred to her as 'ane-san', ignoring her numerous protests not to do so. She continued to tell him he had to attend the current meeting in order to understand Port Mafia's ways. She asked where he got the hat he now had, but their conversation interrupted.

During their walk, Chūya and Dazai run into each other again, displeased and scorning each other. Dazai upset Chūya did not uphold the bet as a dog, and Chūya knowing Dazai rigged the game they played.

During their argument, Koyo questioned Mori on allowing the two in the same group, but Mori assured her it would be fine.

Per the custom of giving new members a new piece of clothing upon officially joining, Mori gifted Rimbaud's old hat to Chūya. He also obtained Rimbaud's old documents of the Arahabaki incident, revealing the military's purpose of using existing abilities combined with existing entities as artificial abilities - implying Chūya as one of their test subjects that ended up as a seal of Arahabaki's existence. Although Mori could not give the full report to Chūya, he explained Executives had full rights to it.

Understanding the situation, Chūya vowed to give his all to the Port Mafia and protect them and the city he loved, Yokohama.

Stormbringer
Incomplete, citations needed. Chūya is first seen as a sixteen year old boy being hosted a party by the Flags, a group of young mafia members under 25 who are all very accomplished in their work. The party is a celebration for Chūya for completing his first year in the mafia, and they present a photo as evidence to them going behind Mori's back to find out Chūya's background, showing he was once an ordinary child who lived in a rural part of Japan. This is quickly interrupted by Adam Frankenstein. He proceeds to have a short fight with the group before explaining his purpose of being there, as a robot agent created by a scientist with the intent on helping humanity. When his attempts at talking to the group prove futile, he grabs Chūya under his arm and runs away with the boy. He explains to Chūya the in danger he's in, from an assassin by the name of Paul Verlaine- and that he was sent on a mission to subjugate the assassin.

Chūya escapes from Adam, only to be caught by Verlaine. Verlaine reveals he slayed the Flags during Chūya's absence, and explains that we wants to kill anyone Chūya has a reason to stay in the Port Mafia/Yokohama for. He tries to bargain with Chūya, referring to himself as Chūya's older brother in a sense of shared inhumanity. This does not go over well, and so he partially opens the 'gate' within the Chūya. This makes Chūya's ability go haywire till Dazai comes to nullify it. Chūya then arrives at the bar, where he witnesses his friends' corpses.

Later, Chūya attended his friends' funeral and cracks the floor in anger when Adam unintentionally angered him by pestering him about having a meeting during the ceremony. However, Chūya was forced to go by Mori and takes Adam to find who else Verlaine may target, Shirase, who works in a factory following the dissolution of the Sheep. Adam is surprised when Chūya is insulted by his former friend, who flees, leading to a chase. Shirase is quickly caught by an officer who happens to know Chūya and they all go to the police station.

At the police station, Chūya is revolted by Adam's attempt at killing time (the "Name Strange Human Traits" game) banned the robot from the game. Chūya asks Adam if he thinks the Port Mafia's lawyer will be able to get Shirase released, to which the robot replies "while possible, it will take a while." explaining the police already found twenty firearms with the serial number scratched off in Shirase home. Additionally the police's real target is Chūya himself, so they will most likely keep Shirase for the full forty-eight hours. When Chūya suggests that maybe Adam can get his boss to pull some strings, he is then informed of the complex international laws regarding Verlaine's case. Adam asks about the Port Mafia's strategist with an ability that could help them trap Verlaine, to which Chūya is angered at the mention of Dazai. He states that he does not trust Dazai and that he cannot get into contact with him anyways.

Dragon's Head Conflict
At sixteen, alongside Dazai as the partnership "Twin Dark" (双黒), the Dragon's Head Conflict came to its peak, devastating all groups of the criminal underground. After Dazai had been captured by the enemy, Chūya stormed the enemy's base on a motorcycle, decimating countless members before reaching an unharmed Dazai. Their bickering continues until more members appear for Chūya to defeat.

When they reach Tatsuhiko Shibusawa, Chūya, enraged at the meaningless deaths of his own subordinates, unleashed Corruption. Successfully quelling Dragon's Head Rush largely on his own, Chūya rose to Executive sooner than anticipated, allowing him access to Rimbaud's documents. Using the information, Chūya found Verlaine alive and well, further clarifying his own origins.

Port Mafia Arc
Chūya arrives after the Port Mafia imprisons Dazai in their torture basement. He mocks Dazai's, revealing in his capture. However, he's soon to catch on that Dazai's capture is suspicious. Thanks to having worked alongside Dazai back in the day, Chūya is fast to notice Dazai is up to something, unlike Akutagawa. Dazai dismisses his suspicions, saying he's just awaiting his execution. Annoyed, Chūya points out that if Dazai really was negligent enough to be bested by the mafia, Chūya claims he would've killed him long ago.

Cutting the conversation short, Chūya says he came solely to harass Dazai. In the past, Dazai went out of his way to trouble both allies and enemies, so now it's Chūya's turn. He breaks Dazai's restraints, his strength nearly taking out the entire pillar holding Dazai up. Although he isn't sure what Dazai has up his sleeve, Chūya challenges Dazai to a fight, ready to put an end to his schemes. After Dazai reveals he could've removed the shackles at any time, Chūya's more than happy to begin the fight.

For much of the fight, Chūya has the upper hand, even saying Dazai's own punch isn't even a massage. He kicks Dazai with enough force to make him crash and crack the wall, but Dazai withstands the attack after blocking it at the right moment. Dazai recalls Chūya's reputation as the strongest martial artist in the Mafia.

Having worked alongside him, however, Dazai knows all of Chūya's attacks, so it's easy for him to defend the worst of it. Annoyed, Chūya moves too fast for Dazai to see. Chūya proceeds to punch and mock Dazai without giving the man any rest. Finally, he pins Dazai to a wall, gripping his throat. He pulls out a knife, pressing it against Dazai's throat and demanding to know what Dazai has up his sleeve.

Dazai reveals the main reason for his actions is for Atsushi's sake. Unimpressed, Chūya says that Dazai's fallen since his reputation as the Port Mafia's youngest executive, saying luck's abandoned him. Having just returned from quelling disputes in the west six months ago, Chūya feels himself lucky knowing he came back after Dazai's been captured. Laughing at him, Dazai warns Chūya of a meeting between the Port Mafia's five leaders. Shocked, Chūya doubts the claim, as such a meeting only takes place every few years to discuss the mafia's future direction. As an Executive, he would know about the meeting. According to Dazai, he sent a letter the other day stating if he dies, the mafia's secrets would be exposed. As his own fate would be discussed during the meeting, if Chūya killed him right now, he'd be viewed as a traitor and either dismissed or killed.

Chūya understands even if he did disregards consequences and killed Dazai, the man would be more than happy to die. With a smile, Dazai confirms the claim, inviting Chūya to hurry up and kill him. Especially since he can die knowing the Port Mafia would be after Chūya because of himself. Dazai's mockery makes something click in Chūya's mind - as in, from the beginning, Dazai intended to push Chūya to the worst conclusion possible.

Frustrated, Chūya backs off. He informs Dazai that Akutagawa leads the hunt for Atsushi, and tells him where the records of who sent the bounty can be found - an archive storage room on the mafia's second floor. He orders Dazai to hurry up his investigation and leave. Just before Chūya leaves him be, he declares their feud isn't over, and that this is the one and only time Chūya intends to spare him.

The Guild Arc
Chūya is seen again with Black Lizard, Kajii, and a group of subordinates bowing down to Mori and reports regarding the assassin from The Guild killed on the spot. As a sign of respect, he takes his hat off and bows to Mori.

Later on, Chūya stands in Mori's office where Elise and Mori are located. He reports that The Guild has attacked them and that Kōyō Ozaki has been captured by the Detective Agency as a prisoner of war. Commenting on the fact that they can't let their guard down since one of their five Executives has been captured, he asks for Mori's direction. To Chūya's surprise, Mori decides to arrange an assassination for Yukichi Fukuzawa.

When the attack is a failure, Chūya surveys the aftermath, from which he reaffirms his belief that hired outsiders cannot be trusted. Reporting to Mori on the attack's failure, Chūya subsequently confirms the success of the Scandium marker transferred onto Fukuzawa, allowing the Mafia to track his location.

Chūya later arrives having infiltrated the railway tunnel leading to the Agency's hideout. He deactivates multiple crucial cameras in the area and renders the automatic gun emplacements Yukichi Fukuzawa activates useless. He mocks the detectives' lack of manpower, challenging them to face him in person. Chūya's prowess forces the Agency's hand, so they send Akiko Yosano and Kenji Miyazawa to approach him. Akiko deduces Chūya isn't here to harm the Agency for once. Found out, Chūya asks where Fukuzawa is. Akiko directs him to a camera, and Chūya declares he has a message from Mori to Fukuzawa. He holds a photograph of John Steinbeck and H.P. Lovecraft to the lens, and on the back is their location and the time, and that the Mafia left bait for the two. The Mafia's intent is to leave the two of them to the Agency.

Instead of humoring him, Akiko and Kenji go in to attack. True to his personality, a fight suits Chūya the best, not being a messenger. He gladly takes part in the fight, impressed with Kenji's strength, however, he's quick to land a kick on Kenji, sending him colliding and breaking the wall. Akiko attempts to attack him from behind, but Chūya uses For the Tainted Sorrow to avoid the attack, standing upside down on the ceiling. Thanks to Dazai, Akiko recognizes he's able to manipulate gravity, much to Chūya's annoyance. He decides to go all out. Although he falls at a reasonable speed, he decimates the ground, proving Akiko and Kenji are no match for h. More than ready to finish them, he asks if either of them are ready to "defy gravity".

Fukuzawa speaks up, acknowledging the mafia's intentions. They wish to use the Agency to eliminate Guild members without lifting a finger. Although Fukuzawa admits this a prudent attempt on Mori's part, he states the Agency isn't so desperate, and if the mafia really thinks that's all it takes to drag the Agency into danger, the mafia is unworthy of being the Agency's enemy. When questioned again, Chūya insists the mafia has no ulterior motives over the plan. Unaware that Ranpo Edogawa listens and watches his answers, Chūya remains confident.

Soon, Ranpo calls Chūya's bluff, demanding to know what the mafia's "bait" actually is. At this, Chūya smiles. He comes clean - the Mafia found and leaked the hideout of the Agency's clerks to the Guild. He mocks the Guild, reciting that Mori knew the Agency would fall for his plan even if they knew it was a trap.

After the Guild captures Q, using Dogra Magra to affect all Yokohama citizens and spiral the city out of control, Chūya leads forces to defend the city, as Yokohama is crucial and the main base of operations for the Mafia. He orders his men and Black Lizard to show no mercy to anyone who attacks them.

In the aftermath, he stands in a shell corporation's building with Mori. The incident left the Mafia 18 dead Mafiosi, and roughly 100 in total, counting sub-organizations. Taking his hat off in respect for the dead, Chūya grudgingly admits that without Dazai's ability, the casualties could have easily reached ten times the amount of deaths. When Koyo arrives, he learns the details of the invitation the Agency sent to the Port Mafia. When the Agency and Mafia arrange a temporary truce, Chūya and Dazai are assigned to work together. Their task is reaching the Guild's hideout where they hide Q. Working together, they form the Port Mafia's former fiercest team - Twin Dark.

Unseen, Chūya's ability sends a boulder flying right onto Lovecraft's face. The Guild's foot soldiers attempt to shoot him down, but the bullets fall on impact with his hand. With great ease, he subdues all the men, leaving them in a pile beneath his feet. Steinbeck attempts to attack, but Chūya kicks him with so much force that he's sent flying through several thick groups of trees. He complains about working with Dazai once again, saying it "stinks to high Heaven".As usual, the two constantly argue. Chūya points out he drank vintage 1889 Pétrus - an expensive wine - the day Dazai abandoned the Mafia, driving home how much he hates Dazai.

Their arguing continues until they finally reach Q. Dazai swipes Chūya's knife, holding it to Q's throat as if to kill him. Chūya reasons he won't be able to stop Dazai in time given their distance. He says when he sees Q, all he can think of and see are the body bags of his subordinates thanks to Q's curse. As a result, he encourages Dazai to kill him. He expresses disgust at Dazai's "goody-two-shoes act" when the man doesn't kill Q. The two discuss the massive difference in harm between the Mafia and Agency. Although the Mafia lost subordinates, the Agency only had Doppo Kunikida affected. Chūya asks what the Agency did, and Dazai claims to have recorded the incident.

Chūya recovers Q, demanding Dazai return his doll. Dazai refuses, irritating Chūya. Once again, they bicker. When Chūya walks out the hideout, a massive tentacle wraps around his neck. He catches sight of the culprit - a mangled Lovecraft before he's thrashed into the wall of the building. After he recovers, he asks Chūya what their next move should be. Dazai brags, saying his ability will just nullify whatever Lovecraft has up his sleeves. After he's attacked, however, both he and Chūya are surprised when No Longer Human fails to nullify The Great Old Ones - as in, it's not an ability.

When Dazai suggests they use a Twin Dark tactic - "Shame and Toad", Chūya argues the tactics "Rain Falls Outside the Window Frame" or "The Fake Flowers Deceit" would be more appropriate. Unfortunately for him, Dazai reminds Chūya he's the strategist behind Twin Dark, and he's never been wrong about a plan before. Chūya begrudgingly accepts this fact. "Shame and Toad" involve Dazai acting as a decoy, whilst Chūya appears from behind at the best moment to attack. Chūya punches Lovecraft straight through the chest, using his gravity manipulation to pin Lovecraft's body to the ground, completely immobilized. Seemingly victorious, Chūya and Dazai argue more, unaware that Lovecraft brute forces his way out of Chūya's ability - not to mention transforming.

Lovecraft attacks Dazai, taking his right arm off. Chūya notices a shadow behind him and turns to see Lovecraft's grotesque, true form looming over him. While he has the opportunity, he rushes to check Dazai's condition. Dazai reveals the arm he 'lost' is fake, and he's almost entirely unharmed. Chūya demands Dazai think of something to deal with the abomination right in front of him. To his dismay, Dazai states Corruption is their only option. It's an ability that allowed Twin Dark to take out the entire base of Dragon's Head, but its effects on Chūya mean that if Dazai is too late to nullify it, Chūya will die. He leaves the decision up to Chūya.

Aware he has no choice, Chūya unleashes Corruption. He discards his gloves and recites a chant. The instant Corruption unleashes, Chūya's hands are covered in red markings, and where he stands breaks under the increased density of his body. In this state, Chūya mindlessly attacks Lovecraft using condensed gravitons - essentially self-made black holes. According to Dazai, Chūya could crush a tank with his bare hands with Corruption. The drawback is that Chūya has no control nor awareness during Corruption - he's just a destructive killing machine that won't stop until his own ability kills him.

It doesn't take long for Chūya to reach his limit. Blood pours out his nose and mouth, showing his body giving out under the strain of Corruption. With little time left, Dazai activates a bomb hidden in Lovecraft's body, combining the explosion with Chūya's black holes, ultimately destroying Lovecraft from the inside-out. By this point, blood falls from Chūya in pools. Mindless to the strain, Chūya proceeds to destroy the rest of the area. Maniacal, he attempts to create another large black hole, but Dazai nullifies Corruption at the last second. Barely conscious, Chūya expresses anger that Dazai waited so long to nullify Corruption, anger worsened when Dazai says he did so for fun. To Chūya, it's yet another violation of trust Dazai takes glee in. He attempts to punch him but passes out. In the end, Dazai leaves him behind.

It's not until he recovers and the Guild has been defeated that Chūya returns. In celebration of victory, he presents a 1964 Romanée-Conti to Mori and Kōyō, the three in a meeting. Kōyō asks if he's sure, knowing the wine to be a prized possession of his. Chūya assures her he'd been saving the wine for such an occasion. The three clink their glasses together, and Chūya asks what Akutagawa's punishment for acting without orders will be. Mori informs him Akutagawa won't be punished, as he succeeded in the Mafia's main goal of taking out the Guild. Whilst Mori and Kōyō converse, Chūya's already drunk before he's even finished his glass.

Cannibalism Arc
After both Mori and Fukuzawa fall ill to a virus equipped to end after one host kills the other, Chūya and Kōyō deliberate on what action to take within two days before the virus kills the two leaders. Bent on crushing the mastermind and despite Kōyō's advice that fighting against the Agency is playing into the enemy's hands, Chūya opts to face the Agency as soon as possible.

The mafia makes their move against the Agency. Chūya leads the attack, setting aside any personal grudges and focusing only on saving Mori's life. He demands the Agency give up Fukuzawa, saying this could end without anyone else dying if they cooperate. He's notified the Agency has Kenji on guard in Fukuzawa's infirmary room, an issue given Kenji's resilience and strength rendering attacks and guns useless. The mafia's assault is further complicated by the entire Agency's guarding the room, forcing Chūya to order a full-on assault with the mafia's main forces.

After Tanizaki and Kyōka infiltrate the mafia's headquarters, Chūya switches gears to return as soon as he can. He's stopped by Ranpo, questioning Ranpo's judgment as he doesn't have a combative ability. Ranpo points out that's true, but Chūya's suffered countless defeats another non-combative - Dazai. Enraged by Ranpo's mockery, Chūya's quick to attack. He finds out too late he fell for Ranpo's trap and is trapped in Edgar Allan Poe's book alongside Ranpo.

Although he later escapes, Ranpo says Chūya got frustrated with the mystery and ended up punching suspects randomly, eventually getting left behind by Ranpo.

Hunting Dogs Arc
Free from Poe's book, Chūya returns on orders to assist the Armed Detective Agency against the Hunting Dogs. Arriving on a helicopter, Chūya saves their lives from Saigiku Jōno and Tetchō Suehiro. Having them board the helicopter, he clarifies his job is not to help the Agency, and that, in fact, Mori and Fukuzawa agreed to have one member of the Agency return with Chūya to the Port Mafia. Tetchō cuts the conversation short, attacking the group with his ability. Kunikida soon jumps off the chopper and detonates a hand grenade on himself and Tetchō to let Chūya and the Agency escape.

Vampire Infection Outbreak Arc
At some point, Chūya gets infected and turns into a vampire. He also arrives at Meursault and assaults entire squads, defeating even their strongest, Briareus. Rescuing Fyodor Dostoevsky from prison forces following his and Dazai's cell escape courtesy of Nikolai Gogol, Chūya turns out to be the Conjurer's next pawn against Dazai and Sigma.

Chūya disposes of Meursault guards as they make their escape. Initially successful in exiting the premises through Fyodor's key card, the two soon come across a wrong passcode and are caught in the middle of a containment shutdown. Under Fyodor's direction, Chūya attempts to break through the walls but to no avail, until they are gradually soaked in heavy water.

Dazai communicates with them from the control room and recalls some instances of his partnership with Chūya as Twin Dark, but he dismisses them and cheerfully bids goodbye to him, leaving Chūya and Fyodor sinking in the heavy water.