Episode 53

Hero vs. Criminal (stylized as HERO VS. CRIMINAL) is the 53rd episode of Bungo Stray Dogs anime series and the third episode of the fifth season.

Synopsis
Atsushi and Akutagawa find themselves cornered, with no choice but to fight Fukuchi and his seemingly insurmountable powers. Combining forces and trusting in one another, do they have what it takes to defeat the mightiest Hunting Dog?

Summary
Two weeks before the Decay of the Angel incident, Akutagawa rendezvouses with Dazai in the forest where they first met. Initially reluctant, Akutagawa accepts to become Dazai's eyes in the forthcoming catastrophe to collect intel, only to lend assistance and save the Agency at the sight of a smoke flare. At present, after Ranpo does so, Akutagawa reveals himself aboard the ship and joins Atsushi in battling Fukuchi.

With the sole intention of disposing Kamui, Akutagawa begins engaging Fukuchi in combat. He claims that he and Atsushi are enough to take him down, recalling how Dazai chose him and Atsushi as a new generation of Twin Dark in preparation for the present calamity. Akutagawa activates Rashōmon and other types to fend against Fukuchi's ability-enhanced resources, but to little avail. Atsushi, having regenerated his previously severed leg, intercepts and saves Akutagawa from getting attacked.

The two flee inside the ship, where Akutagawa chides Atsushi for running away, while Atsushi presses that they cannot win against someone like Fukuchi. Akutagawa vows to defeat Fukuchi no matter what, or Dazai will have no need of him otherwise, and recognizes Atsushi as his trial. As a ship guard spots them, Akutagawa incapacitates him rather than killing him as a way of upholding his promise with Atsushi not to kill anyone within six months.

Akutagawa soon proposes that they combine their powers, which previously proved nearly infallible as an amalgam of their respective abilities, to defeat Fukuchi in a foolproof tactic. They head to the ship's VIP submarine to use as a bait in carrying out their plan, only for Fukuchi to have been awaiting them. Atsushi questions Fukuchi's motives, where the latter narrates his experience of being in the battlefield. Fukuchi thus engages the two in combat and proves to have the superior hand, moreso that the two keep attacking him individually.

Amidst their perserverance to battle Kamui, Fukuchi discards his sword and summons the space–time sword Shintō Amenogozen, effortlessly stabbing Akutagawa and Atsushi by cutting through space. Fukuchi criticizes their lack of trust in each other, which was ideally to optimize Atsushi's abilities in the vanguard and Akutagawa's in the rearguard. Akutagawa merely views the situation as an opportunity to prove himself to Dazai should he be able to defeat someone like Fukuchi.

However, Fukuchi invites Akutagawa to train under him into becoming the strongest ability user among the Hunting Dogs and negotiates to kill Atsushi for him in return, claiming that he has had enough of dispatching children for his objectives. Apparently accepting the offer, Akutagawa reveals having a lung disease, hence why he wishes to prove himself to Dazai in the short time that he has left. Akutagawa and Atsushi then charge at each other, only for Akutagawa to clad Atsushi in his overcoat using Rashōmon and carry out their perfect ambush on Fukuchi, where Atsushi severs Fukuchi's arms.

Fukuchi finally dies, and Atsushi retrieves the page on his person. Atsushi, however, wonders where Amenogozen was cutting at the last minute. Amenogozen turns out to have cut to the past before the ambush, just in time for Fukuchi to sever Atsushi's arm instead and stab Akutagawa from behind. Fukuchi reminds that Amenogozen, as a space–time sword, can traverse through both space and time, explaining Fukuchi's countless victories in the past.

In his final moments, Akutagawa professes his need for actions over words and manipulates his remaining shirt to cut beneath the deck, crushing a fire extinguisher and escaping with Atsushi amidst the smoke. They are able to escape, but Fukuchi uses Amenogozen once more to turn back time before he can do so and prevents their escape, slashing the defenseless Akutagawa's neck.