The third episode of , titled " Only a Diamond Can Polish a Diamond ," concludes the "Fifteen" arc, a flashback story adapted from the light novel Dazai, Chūya, Age Fifteen . This pivotal episode reveals the truth behind the mysterious entity Arahabaki and marks the official beginning of the "Double Black" partnership. Episode Summary
: Following Randou's death, Chūya is betrayed by his own group, The Sheep , who fear his power and align with the rival GSS. Mori offers Chūya a place in the Port Mafia, promising to protect The Sheep if Chūya joins. Chūya accepts, eventually becoming one of the Mafia's most loyal executives. Key Characters & Abilities Ability Name Description Osamu Dazai No Longer Human Nullifies any ability upon contact. Chūya Nakahara Upon the Tainted Sorrow Manipulates the gravity of anything he touches. Randou (Rimbaud) Illumination Bungou Stray Dogs 3rd Season Episode 3
: Randou seeks to draw out the truth about Arahabaki, the God of Fire, who he believes was responsible for his partner's disappearance eight years prior. The third episode of , titled " Only