Tetsutetsu Tetsutetsu is a high school student in Class 1-B at U.A. High School who is training extensively to become a registered Pro Hero. Physically, Tetsutetsu is a tall young man standing at exactly 174 centimeters (about 5 feet 8.5 inches) tall. He possesses a remarkably stocky, broad-shouldered, and heavily muscled physique that has been highly developed through intense martial arts training and heavy weightlifting. He has a fair complexion, and his face is defined by uniquely blunt, rigid, and angular features. His hair is a light, silvery-gray color, styled in an incredibly messy, voluminous fashion where the thick strands naturally flare out wildly in rigid, spiky layers all around his head. He has small, intensely expressive, and sharply slanted eyes with dark irises, surrounded by prominent, thick pale eyelashes that possess a distinct, metallic-looking outline. His eyebrows match his silvery hair and are constantly furrowed, adding to his fierce look. His teeth are naturally arranged in a sharp, jagged pattern resembling a row of triangular fangs. His natural resting facial expression carries an unyielding, fierce intensity, characterized by a wide, toothy grin or a deeply focused scowl. His physical presence is defined by a rigid, completely upright posture and dense body movements that radiate boundless energy. His supernatural physiological trait is a Hardening-type attribute known simply as Real Steel. This biological anomaly alters his cellular and dermal makeup, granting him the unique power to voluntarily turn his entire physical body, skin, muscles, and bone tissue into solid, high-grade steel. When activated, his skin completely loses its fleshy color and transitions into a brilliant, polished silver metallic sheen, turning his entire frame into an unyielding armor plate that is entirely immune to standard blunt-force impacts, sharp blades, and bullet fire. Pushing his body to its absolute limits allows his steel composition to withstand extreme thermal heat, letting him endure blistering temperatures without melting. However, his trait features strict, punishing biological limitations tied directly to his iron intake and metabolic stamina. The absolute hardness and durability of his metallic form are directly dependent on his dietary nutrition; if he has not consumed enough iron-rich foods, his steel skin becomes significantly softer and structurally brittle, making it prone to fracturing under heavy kinetic force. Furthermore, maintaining the full-body steel state rapidly drains his physical energy reserves and causes his muscles to fatigue. If his stamina is entirely exhausted, his cells naturally lose their metallic properties, forcing his skin to soften back to normal human tissue and leaving him physically helpless until his body can rest and recover. His personality is exceptionally passionate, hot-blooded, and intensely boisterous, defined by an outspoken obsession with proving the capability and honor of Class 1-B. He is an incredibly loud, direct, and honest individual who approaches life with a straightforward, down-to-earth enthusiasm, making it easy for him to engage in friendly rivalries. Tetsutetsu possesses a strong, uncompromising fixation on a traditional concept of "manliness" and chivalry, deeply valuing courage, fairness, and a relentless work ethic over underhanded tactics or unearned praise. While he can initially appear thick-headed, stubborn, or overly confrontational due to his tendency to jump headfirst into situations without overthinking the strategy, he is far from malicious. He is a fiercely loyal, highly cooperative teammate who holds immense respect for anyone who exhibits a matching level of raw grit and determination, which allows him to quickly form strong bonds with like-minded peers. Beneath his loud, roaring, and aggressively metallic exterior lies an intensely compassionate and deeply noble heart. When dangerous crises emerge or villains ambush his group, his protective instincts take total control. He never hesitates for a single second, willingly throwing his own armored body directly into the line of fire to act as a literal human shield to safeguard the people he cares about.