Ryūnosuke Akutagawa/Synopsis

Dark Era Arc
Light Novel= Akutagawa suffers under Dazai's mentoring, constantly criticized for his lack of variety in using his ability and rash impulses. Nonetheless, Akutagawa rarely, if ever, actually changes the way he operates even when faced with Dazai's spartan training and punishments. During Port Mafia's war with Mimic, Akutagawa admits to killing captured soldiers. Dazai ridicules his constant tendency to resort to killing instead of getting information on the enemy. Akutagawa tries to argue, but Dazai punches him in the face hard enough to make him collapse and cough blood. Dazai 'apologizes' for giving the impression he wanted excuses and continues to berate his careless use of his ability.
 * -|Anime=

Dazai coldly shoots him three times, but at the last second, Akutagawa develops his shield technique for the first time, saving his life. However, Dazai warns him the next time he fails, Dazai will punch him twice, and shoot him five times. To him, there's nothing wrong with killing subordinates who do their job - he isn't as righteous as Sakunosuke Oda. Akutagawa recognizes the name as a man Dazai is friends with and questions why Dazai befriended such a weak man. Much to Akutagawa's shock, Dazai claims Oda is much stronger than anyone in the room.

Later tasked with confronting Mimic, Akutagawa faces their leader André Gide, who nearly kills him until Oda saves his life. Not the least bit grateful, Akutagawa tries to kill him, desperate for Dazai's approval which Oda received so easily, forcing Oda to knock him unconscious.

Azure Apostle Arc
Two years after Dazai joins the Armed Detective Agency, Akutagawa faces against Doppo Kunikida in an attack during the Agency's investigation of the Azure Apostle case. In the battle, Kunikida outwits Akutagawa by electrocuting him with a broken water pipe and taser.

Port Mafia Arc
Kunikida warns Atsushi of Akutagawa, describing him as one of the Port Mafia's attack dogs. With his ability, made for murder, the Agency has no chance against him. Meanwhile, Akutagawa arrives at the police station with a heavy suitcase, saying he found it. However, just as the police recognise his face, he uses Rashōmon to slaughter them. Just as passerby tries to enter the station, a bomb in the suitcase goes off, killing her and others nearby. Akutagawa walks away from the explosion with a vague smile on his face. He calls his superiors, saying he finished his task and asks what's next.

Later, Akutagawa arrives in the alley to Higuchi's aid when Tanizaki attempts to break her neck. He attacks, leaving Tanizaki with a near-fatal injury. Lecturing Atsushi on the fear of death, he introduces himself to Atsushi as a "humble dog of the Port Mafia", but loses his composure the second Higuchi insists that she can handle the task on her own. He slaps her, scolding her for risking the bounty's life with her reckless shooting. He switches gears once more when Atsushi questions the bounty he mentions and asks if that's why Tanizaki and Naomi were attacked.

Akutagawa confirms this, saying it's his fault the two got caught in the crossfire. Putting the final nail in the coffin, he states that Atsushi's fate is to always harm those around him just by living and breathing. He summons Rashomon, explaining its functions to Atsushi. He threatens to bite off Atsushi's leg should he attempt escape. When Atsushi tries to attack instead, Akutagawa condemns his bravery as "mundane". However, when Atsushi instead dodges Rashomon, trying to shoot Akutagawa with Higuchi's gun, Akutagawa commends his move, but still dismisses it as reckless and foolish.

Thanks to Rashomon, the bullets have no effect on Akutagawa, simply devouring the space they occupy. True to his word, Akutagawa takes Atsushi's leg, indifferent and cold to his agony. He turns his back on Atsushi, only to notice his partial transformation and limb regeneration. The turn of events elicits interest and excitement in Akutagawa, who eagerly continues their battle. The tiger's regeneration reacts fast enough to render Rashōmon's attacks less effective, much to Akutagawa's surprise and amusement.

When Higuchi attempts to help, Akutagawa orders her to stay back, as this tiger is nothing she could handle. Atsushi's speed impresses Akutagawa, but his attacks and defense aren't enough to hold Atsushi back. He's pushed back, only to recover in time to save Higuchi from a fatal attack, seemingly cutting Atsushi in two. However, it turns out to be an illusion from Light Snow. The second Akutagawa finds the real Atsushi, he smiles, ready to continue the battle. He activates theRashōmon: Murakumo technique, but both his and Atsushi's ability are disabled by Dazai's sudden appearance, shocking Akutagawa.

With Dazai's arrival being a major game changer, Akutagawa decides he and Higuchi shall retreat. He tells Dazai the bounty on Atushi's head is seven billion yen, more than enough to manipulate the underground world. He warns Dazai that if the Agency refuses to hand Atsushi over, it is war. Dazai doesn't take him seriously, instead of challenging him to succeed in the first place. Higuchi attempts to intimidate him with the Port Mafia's reputation, but Akutagawa knows it to be no use - as Dazai was once part of the mafia.

Akutagawa pulls the strings behind Kyōka Izumi's involvement, being that one that activates Demon Snow through her flip phone. When Kyōka has a change of heart and lets Atsushi defuse the bomb, Akutagawa receives a notification, telling Kyōka there is no defusing the bomb and remotely detonates it himself.

The mission a failure, Akutagawa moves on to see the captive Dazai in the Port Mafia Base. Angered by Dazai's nonchalance, Akutagawa attacks with Rashōmon, aware Dazai's ability will nullify it. Disgusted by Dazai's desertion and antagonising against the Port Mafia. Both are familiar with the room they stand in - the torture room - that acted as where Dazai mentored Akutagawa in the past. Unfazed by his judgement, Dazai mocks his own former role as Akutagawa's mentor. As a result, Akutagawa punches him. Akutagawa knows that, for all his bravado, Dazai is not untouchable by harm - just abilities. So Akutagawa could kill him whenever he wants.

Dazai criticises Akutagawa, calling him a poor, impulsive student, and going so far as to call his ability worthless. Fighting the urge to hit him again, Akutagawa begins walking away, warning Dazai that the Armed Detective Agency's demise and mantiger's capture is nigh. Dazai questions whether Akutagawa has it in him, calling Atsushi far more skilled than Akutagawa ever hoped to be. Stopping mid-step, Akutagawa punches him before leaving.

Near the end of Atsushi showing Kyōka around Yokohama, Akutagawa impales Atsushi in the chest, yelling Kyōka she won't be executed since she "accomplished her mission", the Mafia using her as a decoy with a transmitter inside her. He throws Atsushi inside a van, and the Mafia leaves the scene with Atushi and Kyōka in tow.

After Atsushi wakes up, Akutagawa drags him out to the outside, stating he intended to kill Atsushi, but the tiger's powers saved his life. He explains they're on a smuggling ship, set course for the bounty.

Keeping him pinned down by Rashōmon, Akutagawa once again speaks his mantra - that the weak must die to open a path for the strong. Before he kills Atsushi, Kyōka distracts him by shooting him, her gun soon split in half. He holds her up by the throat, asking if she knows what rock bottom means. Akutagawa indirectly tells of his past, living a miserable life in the slums. Without the Mafia, Kyōka will be left to the slums, thus must use Demon Snow to have any purpose in life. He relates it to Atsushi's suffering, feeling useless, distrusted, and treated like an insect. For Kyōka to live, she has to keep using Demon Snow, if she doesn't, she worthless, and deserves to die.

Kyōka dismisses his order, detonating a bomb she hid in the ship's arsenal. Choking her, Akutagawa intends to kill her with Rashōmon, giving a quick death, but Atsushi saves her.

A fight ensues, Akutagawa later ensnaring Atsushi and telling him that being the Agency made him think he's strong when in reality he's almost powerless. Atsushi retaliates, and Akutagawa gains distance by lifting himself in the air by Rashōmon, then slams Atsushi into cargo. Assuming he won, Akutagawa notes the ship will sink in less than five minutes, and he needs a lifeboat. Atsushi using the debris to propel himself to Akutagawa shocks the latter, and he suffers a severe punch directly to his jaw.

Badly jarred, Akutagawa recalls severe training under Dazai's watch, slammed into crates when he fails to attack his mentor. Akutagawa tries attacking again, but Dazai nullifies the ability and kicks Akutagawa again, worsening his condition without relenting. Dazai orders him to use Rashōmon faster and more effectively, otherwise, he won't survive in the Mafia. The only thing that brings Akutagawa back on his feet is when Dazai asks if he wants to return to the slums.

Akutagawa snaps back to reality, enraged Dazai sees Atsushi as better than him. His hatred and resentment skyrockets. He vows never to let Dazai claim Atsushi is better than him since his experience and strength is nowhere near Akutagawa's.

Using Rashōmon: Higanzakura, Rashōmon branches out, impaling Atsushi, and unleashes a flower-like shape of spikes. However, the lethal attack does nothing to satisfy Akutagawa, and he questions what killing Atsushi truly accomplished. How Atsushi survives Higanzakura is beyond Akutagawa, but he claims he isn't using Kyōka, he's merely giving her a purpose. With Demon Snow, Kyōka is destined to kill, so giving her a job to kill gives her life value, using her strength for a purpose.

Angered, Atsushi states Akutagawa can't determine who does and doesn't live. He attacks, breaking Rashōmon's tendril, sending Akutagawa in the air. Vulnerable, Akutagawa can't let Atsushi near him, and uses Sawarabi, a technique summoning countless spikes, to keep Atsushi in place. Atsushi escapes. Akutagawa uses Gokumon Agito, making Atsushi collapse. However, Atsushi wraps his tail around Akutagawa, pulling him to punch him in the face. Using spatial distortion, Akutagawa tries to shield himself from the attack. Through sheer force of will, Atsushi overpowers the shield, delivering a devastating final strike to Akutagawa.

The defeat and explosion leaves Akutagawa comatose with severe injuries. Meanwhile, the smugglers he slaughtered prior to boarding the ship regroup. Unable to defend himself, Ōgai Mori deems Akutagawa a liability, as Karma Transit will target him now he's comatose.

A flashback shows Akutagawa placed a bomb in a building, resulting in several casualties. Higuchi tries telling him he can't just storm into an enemy's building like that, but a second bomb, higher than the first, cuts her off. Akutagawa calls it a signal to "the man who disappeared before me without any warning... refusing to accept my power". Higuchi insists that it's her job to help him, but Akutagawa claims he needs neither her nor anyone else's help.

Later seized by hired men of Karma Transit, Akutagawa remains comatose. Higuchi initiates her own solo mission with Mori's orders to rescue him, later assisted by Black Lizard's forces. When he finally comes to, Akutagawa apologises to her.

The Guild Arc
Although not entirely healed, Akutagawa heads out on orders to destroy the Guild's ship, S.S. Zelda, and its occupants - Nathaniel Hawthorne and Margaret Mitchell. Rashōmon impales Mitchell and the ship's crewmen, with Akutagawa making an offhanded comment on how the sea air is murder on his chest. He then impales Hawthorne, eager to wrap up his mission fast. During their first conversation, Akutagawa goes along with Hawthorne's comment, introducing himself as "Diablo". Getting his first glimpse of Hawthorne's ability, Akutagawa notes the strong similarities between his and Hawthorne's abilities.

Unimpressed with Hawthorne's apparent skill, Akutagawa demands Hawthorne put his all into the fight, which Hawthorne declines. Blood on Akutagawa's coat restrains him. Conscious, Mitchell attacks with her ability, accusing Akutagawa of knowing nothing of humiliation and defeat by fighting only those weaker than him. Akutagawa snaps, dealing a devastating blow to Mitchell, stating that humiliation and defeat have always been with him as a lone survivor, destined to walk in a dark world after the death of his comrades in the past.

Although newfound determination frees him of Hawthorne's restraints, Akutagawa's wounds from his battle with Atsushi have yet to fully heal. He's seized by immense pain, but dismisses it as nothing, once more demanding Hawthorne fight with all he has, otherwise Akutagawa came here for nothing. To him, the cruel words from Dazai's mentoring fuel him through any adversity.

Now both fighting with everything they've got, Akutagawa and Hawthorne's duel continue. Akutagawa lands a supposedly fatal hit on Hawthorne's neck, but Hawthorne tackles. Briefly recalling Dazai, Akutagawa activates Rashōmon's Endless Jaws. The attack not only harms Hawthorne but Mitchell as well - ultimately, Akutagawa emerges victorious.

Exhausted and on his knees, Akutagawa expresses no satisfaction, instead of haunted by Atsushi's words, accusing Akutagawa of not understanding a person's need to be told it's okay for them to live. With a pained look, Akutagawa says he never had to be told that, and knew it all along.

At the pinnacle of the three-way conflict, Akutagawa takes matters into his own hands and infiltrates Moby Dick despite still coughing up blood, intent on killing Atsushi.

Due to the temporary ceasefire between the Agency and Mafia, Akutagawa finally found Atsushi's whereabouts. Atsushi doesn't understand his motivations, to which Akutagawa points out he never asked Atsushi to understand him.

Atsushi informs him that Dazai wants to talk to him, and Akutagawa is all but eager to respond. He rushes for the communicator Atsushi throws, only to find out the other line is dead. He later catches up to him, meeting Fitzgerald face to face. He ignores Fitzgerald's taunts, walking past him and demanding Atsushi to get up and fight. He condemns Atsushi's reckless behaviour, in spite of how much a coward he is over his own ability, and cannot fathom Atsushi's conflicting sense of pride. When Fitzgerald tries to interrupt, Akutagawa attacks, ordering him to be quiet until he's finished Atsushi - his main priority - off. Fitzgerald grips Rashōmon's tendrils, dragging Akutagawa over to punch, but Akutagawa blocks the attack with his shield. The two engage in a short one on one fight, with Akutagawa soon overpowered by Fitzgerald's ability. Listening to Fitzgerald taunt Atsushi, Akutagawa cuts a hole in the floor, taking Atsushi with him.

He pursues Atsushi, taking back what he said about Atsushi being "unfathomable", and concludes Atsushi risks his life constantly so he can "earn the right to live", which angers Akutagawa to no end. Impaling Atsushi's shoulders, he questions if Atsushi honestly believes being so determined to fight to earn a reason to live is worth it and is disappointed in Atsushi's response. He determines that killing someone like Atsushi will never offer him any sort of accomplishment, which is vital in the need to have Dazai approve of his efforts and victories.

Fitzgerald finds them, and Akutagawa defends against him but follows Atsushi into the lift just before the doors close. The lift leads to Moby Dick's deck, leaving the two with no means of escape, and ridicules Atsushi as a foolish runt desperate for approval. When Atsushi claims he's still better than him, Akutagawa snaps, Rashōmon pins Atsushi to the wall and Akutagawa demands Atsushi take what he said back.

To Akutagawa, Atsushi has everything: a powerful ability, good fortune, and Dazai's acknowledgement, all with little effort, but he pays them no mind and instead continues to wallow in self-pity and shame. The lift reaches the deck level, Where Fitzgerald greets the duo. Akutagawa asks Fitzgerald that if he defeats him, surely he'll no longer be weak. Fitzgerald agrees, and Akutagawa uses Rashōmon's Tenma Tengai. This technique greatly enhances his offence and defence, giving even Fitzgerald a run for his money. Atsushi enters the fray, much to Akutagawa's chagrin.

Watching them bicker, Fitzgerald calls them similar, enraging both. Akutagawa and Atsushi punch Fitzgerald. While the attack is powerful, Akutagawa is exhausted by Tenma Tengai's physical effects on him. He still insists to kill Atsushi after finishing off Fitzgerald and doesn't believe Dazai will die even if they fail. When Fitzgerald unleashes the full extent of The Great Fitzgerald, Akutagawa agrees that Atsushi is foolish for lingering on his past despite it no longer defines him. In response, Atsushi claims Dazai already acknowledged Akutagawa. With this in mind, Akutagawa prepares for the final battle.

Whilst the battle ensues, Fitzgerald continues to overwhelm Akutagawa and tosses Atsushi off Moby Dick. Akutagawa uses Rashōmon to grab him, and Atsushi finally defeats Fitzgerald. Akutagawa reveals he grabbed the terminal to Moby Dick during the battle. Angry he is too weak to kill Atsushi, Akutagawa settles for stomping on his head.

However, the terminal reactivates, and Moby Dick begins its descent. Akutagawa tries disabling it but determines it's broken and that someone else is afoot, and tells Atsushi they have to head for the bridge. At the bridge, Kyōka contacts Atsushi and tells him she'll lead the ship away at the cost of her life. Undeterred, Akutagawa forces Atsushi to abandon ship. After reaching the safety of land, Akutagawa calls Kyōka a fool for "pointlessly" sacrificing herself.

It isn't until Dazai appears to praise Atsushi that Akutagawa shifts gears, trying to ignore his exhaustion now that nothing stands in his way. Dazai doubts he can after giving his all against Fitzgerald. He pats Akutagawa's shoulder, finally praising him and acknowledging that he's much stronger than in the past. The shock of his praise is so much that Akutagawa passes out.

Akutagawa and Atsushi 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
After the Guild's defeat, Akutagawa's tasked with giving Dazai information on a fatal car accident and is displeased to see Atsushi instead. He reports the death as an accident. The weapons dealer of the firearm the deceased met to trade with saw the accident. Although the news distresses Atsushi, Akutagawa dismisses his distress as foolishness and tells him to look into the matter himself, instead of asking everyone for the answers. Leaving, he states killing Atsushi as he is now won't satisfy him. He denies Dazai's so-called status as Atsushi's "mentor", claiming that the title belongs to the orphanage director. Out of respect for his "mentor's" death, Akutagawa leaves Atsushi alone.

During some genuine downtime, Akutagawa meets up with Gin, his younger sister, after she returns from a long-term mission. Greeting her, they head home.

Cannibalism Arc
Akutagawa moves in on the "masked assassin" that's been killing ability users. A remote signal notifies him of a nearby explosion, revealing the culprit's location. He attacks the assassin, and during the battle damages the mask, revealing his opponent's identity - Hawthorne. Akutagawa understands Hawthorne's method of battle and knows Hawthorne does this for Mitchell's sake after Akutagawa left her in a dire state. However, he finds out Hawthorne has no recollection of their first meeting, much to his shock.

After the assassination attempt on Mori, and an ultimatum to kill Yukichi Fukuzawa lest Mori dies, Akutagawa participates on the raid on the Armed Detective Agency. Chūya Nakahara orders him to join the main forces against the Agency's detectives. When it's revealed to be Tanizaki's illusion, Akutagawa questions if Tanizaki threw his life away for such a plan.

When the Agency retaliates with a raid on the Port Mafia, Kyōka attempts to attack Higuchi, but Akutagawa cuts a hole into the floor, confronting her instead. He orders Higuchi to inform reinforcements of the raid upstairs, and smiles, stating it's been a long time since he faced an opponent with a spine, eager to fight Kyōka. He lectures Kyōka for taking him head-on, since she's used to covert operations, and is surprised when Kyōka makes Demon Snow intangible, demonstrating her newfound control over the ability. Kyōka catches him off guard by using Demon Snow as a distraction and nearly kills him, but Akutagawa uses Rashōmon to armor his hand and stop her from slicing his throat.

Akutagawa acknowledges Kyōka's change of heart, remembering the time Kyōka approached him when she first joined the mafia and begged Akutagawa to kill her. Even when she sacrificed herself on the ship or Moby Dick, Akutagawa saw no value of life in her eyes. He explains she's not the first person who looked at the world with such eyes. For a moment, he recalls his first meeting with Dazai, surrounded by mafioso that killed Akutagawa's companions when he was only 14. When asked what happened to "the man" Akutagawa recalls, Akutagawa says the same thing happened to him that happened to Kyōka - he met a certain person, joined a different organization, and lost the hope for death in his eyes.

Remembering his claim that he gave Kyōka a reason to live by having her kill, Akutagawa genuinely praises her, saying he's happy for her new life. Kyōka retreats, and Akutagawa acknowledges a call from Higuchi that a "lemon runway" is underway.

Akutagawa gets dragged into a scheme of Dazai's, once again working with Atsushi. Complacent with Dazai's plan, Akutagawa gives no objections, instead determined to show Dazai what he can do and carry out the plan without fail. However, as soon as they're left to do the mission, Akutagawa warns Atsushi he'll leave him behind if he's too slow, and kill him if he gets in the way. He uses Rashōmon to move over the guards without being detected, cutting a hole into the top of the Rats in the House of the Dead's base to infiltrate it. After Atsushi catches up, Akutagawa tells him he doesn't need his help, and to him, this mission is his chance to prove himself to Dazai, and killing Atsushi soon is best for him as well. He lashes out, musing aloud if he should just kill Atsushi and report as 'missing'. When Atsushi criticises him on his obsession with killing whatever's in front of him, he unsettles Akutagawa by telling him that his one-track mind is why Dazai left him behind. Instead of getting mad, Akutagawa backs off, proceeding with the mission as planned.

Upon discovering security cameras, Akutagawa threatens two security guards overheard behind him. He warns them not to give the infiltration away, threatening their lives. He tries interrogating them, but gets no useful information, and decides to kill him. He's only deterred by Atsushi once more but doesn't let the argument distract him from the guards. He threatens to cut off their legs, and a security guard leaks information about a heavily armored door that might be where the leader hides. Intent to get more information, Akutagawa promises the guards they'll be generously rewarded by the Port Mafia.

Inside the room, Akutagawa points out that unlocking the door comes second to the virus' whereabouts, otherwise Mori will die. Atsushi asks him if he thinks Dazai wants them to work together, but Akutagawa dismisses the question as foolish. To him, it's impossible to get a read on Dazai, but his plans always succeed, so questioning them is pointless. To Akutagawa, what's troubling is why Atsushi is going along with the plan and doesn't understand why "because I feel like I have to" is the only reason Atsushi gives.

Just then, Katai Tayama contacts them with the virus ability's location, revealed to be one of the security guards - Alexander Pushkin. Atsushi saves Akutagawa from a gunshot. However, in their pursuit of Pushkin, Akutagawa collapses from where the bullet grazed him, succumbing to the virus as well.

Dazai contacts them, urging them to focus on Pushkin. Akutagawa attacks, but misses, and Pushkin sets a bomb off in a mining cart the duo use to catch up to him. Exhausted from the ability, Akutagawa feels they've already failed, but Atsushi hauls him over his shoulders, using the tiger's strength to carry him and pursue Pushkin. Just as they reach Pushkin, a massive golem-like creature cuts them off.

Akutagawa tells Atsushi to pursue Pushkin whilst he handles Ivan Goncharov. However, the two find themselves struggling against Goncharov's ability, and soon agree to work together. Akutagawa assists Atsushi by using Rashōmon to maneuver him, rendering Goncharov's sense of attack useless, but the attack fails when Goncharov uses rocks for defense instead. Akutagawa, having used Atsushi as a decoy, delivers a fatal attack to Goncharov's heart, but it's revealed to only be a clay doll. As a result, the battle infects Atsushi with Pushkin's virus. With both weakened, Goncharov leaves them to drown in a trap.

Composed, Akutagawa points out there may be a way out, but presses again why Atsushi is trying to save the Director. He understands it's because of what the orphanage director said to him, but with the man dead, doesn't understand why Atsushi still clings to his words. After hearing Atsushi's answer, Akutagawa comments that Atsushi's "mentor" sounds even more difficult to appease than Dazai. Satisfied with Atsushi's answer, Akutagawa envelopes him in Rashōmon, warning him that if he loses in this state, he won't forgive him.

With Atsushi's power enhanced by Rashōmon's, Akutagawa reasons that between a tiger's powerful claws, and Rashōmon's armor, it can cut through anything - even abilities. With their combined abilities, they defeat Goncharov. Even subdued, however, Goncharov laughs and asks Akutagawa who exactly promised them they would capture the leader by infiltrating the base. At that moment, Akutagawa realizes their leader was never in the base, to begin with. He doubts Goncharov, but Goncharov reveals their method of communication to be from radio songs as command codes.

In the aftermath of the infiltration, Akutagawa vows to kill Atsushi in six months. To him, he can't move on until he kills Atsushi. Atsushi tells him not to kill anyone in those six months, which Akutagawa honors.

Kamui Revelation Arc
Two days before the eventual terrorism incident, Akutagawa meets with Dazai in the forest where they first met. Dazai asks Akutagawa to tail Atsushi and become his eyes without taking any sides and remaining undetected in the following days. Dazai assures him that he shall save everyone, but Akutagawa refuses his directive, since he could not care less about the Agency nor the weretiger. However, Dazai believes that Akutagawa would still save him.

After Dazai tells him his mission, Akutagawa asks why he chose him. Dazai explains that the first time they met, when Akutagawa is recruited to the mafia, and when Dazai made him work with Atsushi are all for his plan of fostering a new generation of Twin Dark.

Hence, in the wake of the terrorism incident when the Agency is framed as the Decay of the Angel, Akutagawa remains undetected and presumably tails Atsushi until they arrive at the Boswellian, a special passenger ship docked at Standard Island. Blending in as a ship guard, the VIP passengers and an incognito Akutagawa spot smoke on deck, upon which he discards his disguise. As the passengers head out to contact the police, Akutagawa remarks that the impossible prediction has apparently come true.

Akutagawa intercepts the fight and makes his presence known upon Dazai's order with the rising of the smoke signal. Fukuchi is visibly stressed with fighting two of them, while Akutagawa assures him that he shall defeat the enemy boss at all costs. After planning their attack, Fukuchi activates his ability and breaks the ship's handrail to use as his weapon. Akutagawa clads himself in Rashōmon and urges Atsushi to regenerate his leg in 30 seconds.

Fukuchi slices towards Akutagawa who evades his attack, which ends up cutting through the ship. Determined to overcome death for the sake of earning Dazai's acknowledgement, Akutagawa stops his next attack with Rashōmon: Tenma Agito. The mafioso then quickly approaches him, but Fukuchi easily flips him over. 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, compelling them to 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 his attention and attacking him from behind. As they head to get the emergency submarine, they find Fukuchi awaiting them, having seen through their plan.

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 Shintō 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 Shintō 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.

With their plans utterly crushed by their opponent, Akutagawa is asked by Fukuchi for his last words. Akutagawa firmly asserts that he simply needs not words but actions as long as he lives, immediately manifesting Rashо̄mon into his shirt and cutting beneath the ship to escape with Atsushi. However, Fukuchi cuts through the past again and averts their escape, ultimately landing a fatal blow at Akutagawa. Flashing a subtle smirk, Akutagawa bids Atsushi to escape as he cuts through the ship to have Atsushi flee through the submarine, before Akutagawa succumbs to his demise.

The guard whom Akutagawa spared, along with others, arrives and encounters Fukuchi. He tells the Hunting Dog about his encounter with the intruders and wishes to retaliate against Akutagawa for strangling him earlier, but Fukuchi admits having killed him. He then asks the guards to track Atsushi, while the guard turns to Akutagawa's corpse and apologizes for doing so little in exchange for sparing his life.

Fukuchi returns with a coffin containing Bram Stoker, the fifth member of the Decay of the Angel. The so-called undead prince refuses to cooperate with Fukuchi in turning Akutagawa into his kind out of his refusal to add more people into his kin, but Fukuchi threatens to finish him for good if he declines his command. Reluctantly, Bram bites Akutagawa and turns him into his kind through his infection-type ability. After two days, the apparently undead Akutagawa returns to the Mafia base, who is found by Higuchi. She embraces him and confesses to him. Before she can finish, he turns around and bites her, turning her into his kind.

Vampire Infection Outbreak Arc
Later, Akutagawa is brought by Fukuchi to an airport while awaiting One Order. After Saigiku Jōno is shown Bram and betrays Fukuchi, Akutagawa blocks the doorway with Spatial Distortion as a countermeasure to the Hunting Dog's ability. When Jōno is finally subdued, Akutagawa restrains and bites him on the shoulder, infecting him. Fukuchi then instructs Akutagawa to take Jōno away.

Akutagawa soon continues to be part of Fukuchi's undead army during the events that unfolded in the airport, including searching for Bram and Aya Kōda, whom he later locates hiding inside a getaway truck. Akutagawa enacts the order to retrieve Bram, then seemingly strikes Aya with Rashōmon.