Chūya Nakahara became Arahabaki's human vessel at age seven, devoid of memories preceding this transformation. Arthur Rimbaud's breach of a military facility triggered Arahabaki's catastrophic release, forging Suribachi City and binding Chūya as the singularity's containment seal. An unknown hand rescued him from the ruins, leading to years questioning his humanity due to absent dreams and fragmented identity. By age eight, he protected the youth group Sheep using his gravity manipulation. His unwavering loyalty persisted until fifteen, when the Port Mafia framed him for an Arahabaki-powered attack. During the investigation, Port Mafia leader Ōgai Mori forced a partnership with Osamu Dazai, holding Sheep members hostage. Their collaboration exposed Rimbaud as the incident's instigator and revealed Chūya's origin as an artificial life form forged to contain Arahabaki. Following Rimbaud's death, the Sheep betrayed Chūya, joining the GSS to assassinate him. Dazai dismantled the Sheep, leaving Chūya no haven but the Port Mafia. Mori secured his allegiance by withholding classified documents on his origins, pledging full disclosure upon executive promotion. As a Port Mafia executive, Chūya refined his combat skills, emerging as their supreme martial artist and formidable enforcer. His ability "Upon the Tainted Sorrow" enables pinpoint gravity control for flight, projectile deflection, and environmental devastation. Its true form, "Corruption," unleashes Arahabaki's full destructive might, generating pseudo-black holes and multiplying his strength exponentially. This state induces uncontrollable rampage, severe bodily decay, and eventual death unless halted by Dazai's ability. Activation requires the phrase "Oh, Grantors of Dark Disgrace. Do Not Wake Me Again," drawn from Nakahara's poem "Sheep Song." Chūya's fiery temperament coexists with fierce loyalty. He displays combat arrogance and visceral hatred toward Dazai, who incessantly mocks his stature. Despite ruthlessness, he shuns gratuitous brutality, showing disgust for corpse desecration and honoring debts—like sparing Ango Sakaguchi over a past favor. His leadership diverges from peers; he values subordinates' lives and grieves their losses. Deep insecurities about his humanity eased after Rimbaud's dying affirmation of his personhood, though he retained philosophical detachment from violence, symbolized by his glove-wearing during fights. Key developments encompass the Dragon's Head Conflict, where he lost comrades like the Flags, and the "Storm Bringer" novel events confronting his creator Paul Verlaine. During the Hunting Dogs arc, he infiltrated a prison disguised as a vampire using contacts and artificial fangs to support Dazai's plan, demonstrating strategic adaptability amid their enmity. His signature black hat, inherited from Rimbaud, serves as a memento of their clash and a Corruption trigger.