Chūya Nakahara originated within a government facility housing the destructive entity Arahabaki. At age seven, Arthur Rimbaud's failed attempt to steal Arahabaki triggered the entity's release. This event obliterated the facility, created Suribachi City, and erased Chūya's memories prior to that age, leaving him questioning his humanity due to his connection to the godlike force. Rescued from the ruins, Chūya joined the youth gang, the Sheep, in the slums. Serving as their primary enforcer, he protected their territory using his gravity-manipulation ability, Upon the Tainted Sorrow. Though not their formal leader, he felt deep responsibility for the group's safety. At fifteen, the Sheep were attacked by the Port Mafia. Chūya hunted the perpetrators, encountering Port Mafia executive Ōgai Mori. Mori took Sheep members hostage to force Chūya's cooperation in investigating Arahabaki, pairing him with Osamu Dazai. Their investigation uncovered Rimbaud's role. Chūya confronted and fatally wounded Rimbaud but listened to his dying words urging him to live as a human, profoundly impacting his self-perception. Shortly after, the Sheep betrayed Chūya, allying with the GSS to assassinate him. Stabbed and left for dead, Dazai rescued him, offering a place in the Port Mafia in exchange for sparing the Sheep. Chūya agreed, recognizing Dazai's manipulation yet choosing loyalty to the organization. As a Port Mafia executive, Chūya adopted a black hat gifted by Mori, originally Rimbaud's, symbolizing his new allegiance. He trained under Kōyō Ozaki, whom he calls "ane-san." His tenure involved conflicts with groups like the Guild and Armed Detective Agency, where he demonstrated strategic restraint despite his temper, halting battles when negotiations served the Mafia's interests. Chūya's ability manipulates gravity, enabling flight, projectile redirection, and environmental control. Its true form, Corruption, unleashes Arahabaki's destructive power via the chant: "Oh, Grantors of Dark Disgrace, Do Not Wake Me Again." This state renders him uncontrollable, requiring Dazai's ability-nullification to end it. Their fraught partnership, "Twin Dark," involved high-risk missions like the Dragon's Head Conflict, where Chūya lost six comrades. Chūya is volatile yet principled. He despises betrayal, unnecessary cruelty, and disrespect toward the dead, condemning actions like Dazai's desecration of a corpse. His loyalty is absolute, extending to subordinates and allies like the Flags, whom he mourned deeply. Insecurity about his height and nonhuman origins persists, often exploited by Dazai to provoke him. Key developments include the **Stormbringer Arc**, where he learned he was a government-engineered clone designed to contain Arahabaki. Despite his artificial origins, he reaffirmed loyalty to the Port Mafia as his true family. In the **Dead Apple Film**, he used Corruption to combat a reality-warping enemy, trusting Dazai to nullify it despite their enmity, highlighting their codependency. During the **Vampirization Arc**, he was temporarily turned into a vampire but later cured, his physical resilience allowing him to resist the infection longer than others. Chūya's growth involves accepting his humanity. He maintains self-imposed limits, like fighting without removing his gloves to preserve the "rush" of battle, making exceptions only during Corruption or life-threatening scenarios.