Eijiro Kirishima, born October 16, wields the Quirk *Hardening*, enabling him to solidify and sharpen body parts for offense or defense. The ability first surfaced at age three when a hardened hand accidentally scratched his right eye, leaving a lasting scar and seeding early insecurity about his power. This doubt lingered into junior high, amplified after witnessing Mina Ashido’s heroic display, which made his Quirk seem inferior. A transformative encounter with Crimson Riot—a retro hero championing chivalry—redefined Kirishima’s outlook, inspiring him to adopt a bold red spiked hairstyle as an emblem of courage. Driven by loyalty and a fervent admiration for bravery, Kirishima evaluates actions through a binary of “manly” (embodying honesty, grit, and sacrifice) or “unmanly” (cowardice or deceit). This ethos compels him to defy authority when necessary, exemplified by his resolve to rescue Katsuki Bakugo from villains despite institutional prohibitions. His bond with Bakugo thrives on mutual respect, forged through shared combat tenacity that earns him recognition as Bakugo’s equal. Muscular and standing around 170 cm, Kirishima’s spiky red hair, sharp teeth, and battle-centric hero costume—featuring gear-shaped shoulder pads, a jagged sash, and oni-inspired facial armor—mirror his aggressive yet protective style. *Hardening*’s drawbacks include restricted mobility during activation, a standard duration of ten minutes, and extreme exhaustion after deploying *Red Riot Unbreakable*, a near-invulnerable state lasting 30–40 seconds. Notable techniques include *Red Counter*, a defensive retaliation move, and *Red Gauntlet*, a high-impact charging strike. His durability withstands explosions, bullets, and blunt force, though prolonged use strains stamina. Joint training with Tetsutetsu Tetsutetsu revealed a unique adaptation: repeated damage during hardening boosts subsequent activation density, enhancing resilience. Pivotal battles, like aiding Fat Gum against Kendo Rappa, crystallized Kirishima’s resolve to act despite fear, solidifying his identity as a hero who shields others. This evolution—from self-doubt to unshakable resolve—culminates in his recognition among top classmates, marking his journey toward unwavering determination.