Giyū Tomioka holds the position of Water Hashira in the Demon Slayer Corps. His past is defined by severe trauma, starting with the death of his sister Tsutako; she sacrificed herself shielding him from a demon on her wedding day. This tragedy led to his recruitment and training under Sakonji Urokodaki, where he forged a close bond with fellow apprentice Sabito. Sabito died saving others during the Final Selection exam, leaving Giyū burdened by survivor's guilt and a deep-seated inferiority complex. He became convinced Sabito deserved the Water Hashira title more, a belief that later drove him to contemplate abandoning his position. Giyū maintains a reserved and stoic exterior, often keeping an emotional distance from others. His appearance features messy black hair tied in a low ponytail, sharp blue eyes, and the standard Demon Slayer uniform, complemented by a unique split-pattern haori: one solid red half honoring Tsutako and one geometrically patterned half (green, orange, and yellow) in memory of Sabito. Following the battle against Muzan Kibutsuji, he loses his right arm, adopts shorter hair, and is later seen wearing traditional kimono and hakama pants. Personality-wise, Giyū possesses a strong sense of justice but struggles with social interactions, leading to misunderstandings among his peers. Some fellow Hashira, notably Sanemi Shinazugawa and Obanai Iguro, interpret his aloofness as arrogance. He remains unaware of this animosity until Shinobu Kocho informs him, causing him surprise. Despite his reserved nature, he demonstrates profound loyalty to those he values. This loyalty manifests when he violates the Demon Slayer Corps' code to protect Nezuko Kamado, pledging to commit seppuku should she harm a human, and physically intervening to shield her from Shinobu's attacks. His combat prowess is significant. As a Hashira, Giyū masters Water Breathing and develops a unique eleventh form, "Dead Calm," capable of nullifying incoming attacks. During his fierce battle against Upper Rank Three Akaza, he awakens his Demon Slayer Mark—a water-like design appearing on his left cheek—which enhances his speed, precision, and endurance. Akaza himself acknowledges Giyū's refined swordsmanship, noting he hadn't encountered a Water Hashira of comparable skill in fifty years. Giyū plays a critical role in the final confrontation with Muzan, where his Nichirin Blade turns crimson to hinder demonic regeneration. He sustains severe injuries, including the loss of his arm, yet persists until Muzan's defeat. Key interactions shape his journey. His first meeting with Tanjiro and Nezuko Kamado sets his arc in motion; witnessing Nezuko protect Tanjiro instead of attacking humans, he spares her and directs them to Urokodaki. During the Mount Natagumo mission, he rescues Inosuke Hashibira and kills the Father Spider Demon and Lower Rank Five Rui. He later defends Nezuko at the Hashira meeting, though he remains silent as Sanemi Shinazugawa provokes her. His survivor's guilt culminates when he refuses to participate in Hashira Training, deeming himself unworthy. Tanjiro helps him overcome this by urging him to value his life and honor those who died protecting him. In later arcs, Giyū fights alongside Tanjiro against Akaza and Muzan. When Tanjiro temporarily becomes a demon, Giyū is the first to confront him, prioritizing protection over their bond. After Muzan's defeat and the disbanding of the Demon Slayer Corps, he retires as one of the last surviving Hashira. His demeanor softens, evidenced by smiles directed at the Kamado siblings and Sanemi, signaling reconciliation and personal growth.