Tetsutetsu Tetsutetsu, a student in U.A. High School’s Class 1-B, possesses a hotheaded demeanor and an unyielding resolve, traits amplified by his Quirk: the ability to transform his body into steel. His striking appearance features chin-length gray hair, black eyes framed by thick jagged lashes, and sharp teeth, often drawing comparisons to Eijiro Kirishima. His hero costume includes a dark green jumpsuit reinforced with steel straps, a metal jaw-guard etched with the symbol "Fe," and sturdy boots. Post-graduation, his hair is trimmed shorter as he ascends to the rank of No. 26 pro hero. Driven by a fierce determination to showcase Class 1-B’s strength, Tetsutetsu adopts a bold, direct combat style, clashing frequently with rivals like Katsuki Bakugo. Yet his rivalry with Kirishima evolves into mutual respect, rooted in their shared steel-hardening Quirks and internships under Fourth Kind. Their competitive bond peaks during the Sports Festival’s arm-wrestling match, where Tetsutetsu’s iron deficiency leads to a close defeat. In pivotal battles, his resilience shines. Facing Mustard at the Forest Training Camp, he withstands poison gas and bullets to shield Itsuka Kendo, overpowering the villain despite Quirk exhaustion. During the Joint Training Battle, he exploits his steel form’s heat resistance to neutralize Shoto Todoroki’s ice and fire, forcing a draw when a collapsing tower immobilizes both teams. His Steel Quirk enhances durability and strength but demands iron consumption to stave off fatigue-induced brittleness. Collaborative maneuvers like the Horn Dash Hammer with Pony Tsunotori and the heat-activated Heatetsu form underscore his tactical adaptability, though magnetism and extreme temperatures remain vulnerabilities. Loyalty defines his interactions. He prioritizes allies’ safety, intercepting bullets for Kendo and aiding Ibara Shiozaki’s evacuation during the camp attack. His partnership with Kendo grows into a steadfast alliance, marked by mutual support in missions and school events like the U.A. Festival, where he admires her leadership. Post-graduation collaborations with Fat Gum and Kirishima solidify his heroic reputation, including neutralizing threats like Mustard. His journey from impulsive student to disciplined pro hero embodies relentless perseverance, epitomizing his creed that limits exist only to be shattered.