BEAST Chapter 21

Truth is the 21st chapter of the Bungo Stray BEAST manga.

Summary
Atsushi is unable to defend himself against Akutagawa's Rashōmon: Silver Torrent, which sends him flying off in great impact that gets felt throughout the area. With Atsushi defeated, he requests Akutagawa to end his life as atonement for failing to uphold his promise to the orphanage director. As Akutagawa stomps on his torso, Atsushi apologizes to the director as someone not worthy of the latter's praise.

However, Akutagawa simply ends their fight, as he claims that the Agency does not grant others' wish to die. Instead, he advises Atsushi that running from his past and continuing to live in fear of himself are part of his battles; he also warns the mafioso that he shall overcome and mock him the instance he winds up defeated in such fight.

Dazai finally arrives at the rooftop and commends the fight between the two, describing it to rival even their battle on the ship. As he ponders about Akutagawa's victory as part of the Agency, defeating even Atsushi who was trained by Dazai himself, the Mafia boss fires Atsushi and instructs him to live in the outside world together with Kyōka, much to Atsushi's surprise.

Akutagawa faces Dazai to force the truth out of him, to which Dazai explains that everything since Akutagawa's separation from his sister is all for the sake of the circumstances they are now in. He tells them of the Book, the tool that has forged their world, though still their "reality", that they live in apart from the real world and various other possible worlds. Dazai also reveals having used his nullifying ability to create a singularity and read the memories of his real self outside the Book.

In the end, he warns them of the advancing forces who would begin their invasion of Yokohama in pursuit of the Book and urges the two to eliminate them and protect the Book. Akutagawa is unsatisfied with his explanation, though Dazai asserts that it all boils down to have the two of them interact with and understand each other through clashing with their abilities and souls. The Mafia boss then walks to the edge of the rooftop, much to Atsushi's unease. However, ignoring his plea, Dazai instructs them not to tell anyone about the information he told them, as their world shall destabilize once three or more people gain such knowledge.

Entrusting everything else in their hands, Dazai declares the fifth and final stage of his plan. Akutagawa asks why he is so fixated on their world, to which Dazai muses to himself that it is the only world where Oda lives and writes novels, hence a world which he must not let disappear. In his final thoughts, Dazai regrets not being able to read Oda's novel by the time he finishes it, considering it the one disappointing thing as he jumps off the rooftop. Unable to stop his suicide, Atsushi and Akutagawa look on to the fallen Mafia boss with utter shock.

Abilities

 * Rashōmon
 * Beast Beneath the Moonlight
 * No Longer Human (flashback)