Eijiro Kirishima trains as a professional hero at U.A. High School. He possesses a muscular physique, spiky red hair styled with gel, red eyes, pointed teeth, and a small scar above his right eye. This hairstyle, chosen upon entering U.A., replaces his natural black, shoulder-length hair from middle school, marking a personal shift. His hero costume features dark red gear-shaped shoulder pads, a jagged sash, a red belt with an "R" buckle, black pants, a red half-cape, and a wired face guard resembling an oni. Eight years after the Final War, he stands taller and bulkier, with longer, spikier hair and an updated costume including a longer half-cape. Kirishima champions ideals of courage and chivalry, frequently labeling admirable actions "manly." He is boisterous, outgoing, and deeply values bravery, determination, and selflessness, often moved to tears by such displays. Driven by guilt over past cowardice – failing to help a bullied underclassman and freezing during a villain incident while classmate Mina Ashido acted – he adopted a personal code to live without regret. Watching an interview of his idol, the retro hero Crimson Riot, inspired his hero name "Red Riot" and core ideals. Despite projecting confidence, Kirishima harbors self-doubt about his Quirk's perceived lack of flashiness and his suitability for hero work, fueling relentless training. His Quirk, "Hardening," solidifies his skin into a rock-like state, boosting durability and offense. This hardened form can resist bullets and powerful impacts but weakens under sustained damage, causing fatigue. Kirishima developed specialized techniques: "Red Counter" (counterattacking after hardening), "Red Gauntlet" (a high-speed dash punch), and "Red Riot Unbreakable" (maximum durability for brief periods). Beyond his Quirk, he exhibits natural physical resilience and an indomitable will, frequently shielding allies or civilians. His combat skills placed him second in the U.A. Entrance Exam and eighth in the Quirk Apprehension Test. Key relationships shape Kirishima's path. His friendship with Katsuki Bakugo ignited during the U.S.J. incident when they fought villains side-by-side. Kirishima admires Bakugo's strength and conviction, often softening Bakugo's abrasiveness and rallying classmates to rescue him during the Forest Training Camp Arc. Bakugo respects Kirishima as an equal, acknowledging his resolve and occasionally offering encouragement. With Mina Ashido, Kirishima shares a history from middle school where her courage underscored his insecurities. Her ongoing support – teasing his "horn buddies" hairstyle or creating the "Acidman" move inspired by his "Unbreakable" – reinforces his growth. He credits her as a lifelong inspiration and partners with her in battles, notably saving her from Gigantomachia during the Paranormal Liberation War. In the "Make It! Do-or-Die Survival Training" OVA, Kirishima participates in a disaster rescue exercise within a collapsing shopping mall. Teamed with Bakugo and Denki Kaminari, he searches for a training dummy. He demonstrates practicality, protecting Kaminari from falling debris with his Hardening and aiding Bakugo's plan to restore emergency power. His actions help stabilize the environment for other teams, like subduing Fumikage Tokoyami's out-of-control Dark Shadow. Trapped with Bakugo and Kaminari amid rising water, Kirishima assists in locating and securing the dummy before coordinating with Shoto Todoroki and Izuku Midoriya for escape, highlighting his role as a reliable protector and team player. Kirishima's journey culminates as the No. 12 Pro Hero, working alongside Fat Gum after graduation. He maintains his commitment to resilience and self-improvement, evident in battles like the Shie Hassaikai Raid, where he endured Kendo Rappa's punches to protect Fat Gum, earning his adversary's respect. His resolve extends to major conflicts, including the Final War where he helped block attacks from Tomura Shigaraki. Evolving from a self-doubting student to a confident hero, Kirishima embodies his creed to "never regret anything," solidifying his identity as Red Riot.