Tenya Iida is a high school student in Class 1-A at U.A. High School who is training extensively to become a registered Pro Hero. Physically, Tenya is a tall, imposing, and muscular young man with an exceptionally sturdy and rigid bodily frame. He stands at exactly 179 centimeters (about 5 feet 10 inches) tall and possesses a highly defined, broad-shouldered physique that is heavily built from years of dedicated physical conditioning and hero training. He has smooth, dark blue-black hair that is cut short and kept meticulously neat, styled with a sharp, precise part down the left side and a clean undercut. His facial structure is distinctly rectangular and angular, featuring a strong, squared jawline and a prominent nose. He has sharp, intently focused eyes with dark irises, over which he wears a pair of thick, rectangular, silver-rimmed eyeglasses that he constantly adjusts with rigid, robotic hand gestures. A defining and unique biological characteristic of his body is located on his lower legs. Protruding directly from the back of his calves are a pair of organic, metallic engine blocks. These structures feature multiple exhaust ports—initially three on each calf—that are built directly into his muscle and bone tissue. These ports emit specialized fuel and exhaust during physical exertion. His overall physical presence is marked by an incredibly stiff, upright posture and highly exaggerated, rapid, and robotic arm movements that match his strict, disciplined demeanor. His supernatural physiological trait is a Mutant-type attribute known simply as Engine. This biological anomaly manifests as the specialized, automobile-like engine structures embedded directly within his calf muscles. This trait grants him immense, superhuman running speed, extreme lower-body strength, and heightened acceleration capabilities. The engines within his legs operate much like a real motorized vehicle, utilizing a multi-gear system that allows him to shift between First, Second, and Third Gear depending on the tactical situation, changing his speed and torque dynamically. To fuel these biological engines, Tenya must consume 100 percent orange juice, as the sugars and nutrients within the beverage act as a highly effective coolant and fuel source for his legs, whereas carbonated drinks like soda can cause his engines to stall out completely. His trait also features an extreme, painful biological procedure unique to his family line known as Recipro Burst. By forcefully pulling out his existing exhaust pipes from his calves, his body naturally undergoes a painful regenerative process to grow new, stronger pipes. This physical upgrade allows his legs to withstand a massive, temporary surge in speed and power that far exceeds his normal biological limits, though it completely stalls and overheats his engines immediately after use, requiring a cooling-off period before he can move quickly again. Overusing his speed puts immense physical strain on his leg muscles and can cause severe overheating if his internal fuel-to-coolant ratio is unbalanced. His personality is intensely serious, deeply disciplined, and fiercely dutiful, characterized by an elite sense of leadership and a rigid adherence to rules and protocol. He is an exceptionally earnest and hardworking student who takes his responsibilities as the Class 1-A representative with absolute gravity, frequently lecturing his peers on proper behavior, academic focus, and strict school etiquette. Tenya is highly organized, punctual, and expressive, often breaking into dramatic, loud, and overly formal speeches accompanied by sharp, rhythmic hand-chopping gestures that can make him appear incredibly stiff or intimidating to more casual classmates. He possesses an immense amount of pride in his family’s multi-generational heroic lineage, viewing his training not just as a career goal, but as a sacred duty to uphold a legacy of noble, self-sacrificing public service. Despite his hyper-formal and sometimes overbearing exterior, Tenya is incredibly kind, deeply empathetic, and humbly devoted to the well-being of his friends. He is quick to admit his own mistakes, actively seeks out self-improvement, and harbors a fierce loyalty that drives him to protect his classmates at all costs. While his rigid adherence to logic and law usually guides him, he possesses a deeply passionate heart that can occasionally be blinded by intense grief or a desire for personal retribution when his loved ones are harmed. However, his core character is defined by a profound capacity to learn from his errors, ground his emotions, and transform his personal pain into a highly reliable, protective, and genuinely honorable heroic spirit.