Ken Ishiyama, recognized by the hero name Cementoss, balances dual roles as a modern literature instructor and Pro Hero at U.A. High School. His towering form evokes a humanoid structure of solid cement, characterized by perpetually shut eyes, slate-gray hair secured in a truncated ponytail, and a rigid, angular physique. He dons a sleeveless brown hero suit accented by yellow stripes, paired with shorts, an extended collar, and gray footwear featuring yellow soles. Injuries sustained during the Paranormal Liberation War against Geten leave him with a scar tracing his left arm and a metallic plate embedded along his right torso. Committed to safeguarding others, Cementoss intervenes decisively—halting Eijiro Kirishima’s near-exposure of All Might’s hidden identity and shielding Izuku Midoriya from physical collapse during a clash with Shoto Todoroki. In battle, he exemplifies unwavering resolve, publicly affirming his readiness to sacrifice his life as a Pro Hero, embracing the mantle of society’s “guardian” to ensure civilian safety. His Quirk, Cement, grants mastery over existing cement materials through touch, enabling him to reshape urban landscapes into walls, traps, or elevated platforms. While reliant on accessible cement—advantageous in cities but restrictive in rural zones—his expertise manifests in rapid construction of intricate arenas like Gym Gamma and the U.A. Sports Festival stadium. During the Paranormal Liberation War, he strategically dismantles segments of Gunga Mountain Villa to flush out adversaries. For U.A.’s Final Exams, Cementoss and fellow teachers employ weighted restraints to self-handicap, ensuring equitable evaluations of student combat prowess. He challenges pupils like Kirishima and Rikido Sato with formidable cement barriers, testing their capacity to breach fortified defenses. Cementoss holds professional respect for All Might’s legacy, counseling prudence regarding the retired hero’s health. His battlefield contributions prove vital during pivotal operations, including the Paranormal Liberation War, where his Quirk disrupts enemy strategies through terrain manipulation and structural control.