Shota Aizawa serves as homeroom teacher for U.A. High School's Class 1-A and operates professionally as the underground Pro Hero Eraser Head. Tall and slender with pale skin, his appearance features messy shoulder-length black hair and perpetually tired-looking black eyes that glow red when activating his Quirk. His standard black jumpsuit, utility belt, boots, and signature white capture weapon – constructed from steel wire alloy and carbon nanofibers – are complemented by yellow goggles worn in combat to hide his line of sight. Significant battles left him with a scar under his right eye from the Unforeseen Simulation Joint incident, a later vertical scar across the same eye, and eventual loss of that eye requiring an eyepatch. During the Paranormal Liberation War, he self-amputated his right leg to prevent a quirk-erasing bullet from nullifying his ability, replacing it with a prosthetic. Aizawa presents a stern, apathetic, and reserved demeanor, prioritizing logic over social interaction. He frequently appears fatigued, napping in a sleeping bag or consuming nutrient jelly packs. As a teacher, he enforces high expectations and rigorous training, famously threatening expulsion for underperformance—later revealed as "logical ruses" to motivate students, with reinstatements common. Despite his harsh exterior, he deeply cares for his students' safety and development, risking his life to protect them and strategically bolstering their confidence, such as allowing capture during Momo Yaoyorozu's exam. This protectiveness extends to Eri, a young girl with uncontrollable Rewind abilities, whom he guardians and safeguards using his Quirk. His commitment stems partly from past trauma: his friend Oboro Shirakumo died during their U.A. student days, and Oboro's corpse was later converted into the Nomu Kurogiri. This loss profoundly shaped Aizawa's teaching philosophy, pushing students to avoid needless sacrifice while ensuring they become long-lived, inspiring heroes. Confronting Kurogiri to reach Oboro's consciousness reduced him to tears, revealing unresolved grief. His Quirk, Erasure, nullifies others' Quirks through eye contact, deactivating upon blinking or broken line of sight. Prolonged use causes severe dry eye, managed with eye drops, and his injuries have reduced its sustained effectiveness. Mutant-type Quirks remain unaffected. To compensate, he mastered a unique fighting style over six years called Binding Cloth, utilizing his capture weapon for mobility, restraint, and combat synergy with his Quirk. He excels in hand-to-hand combat, agility-based evasion, and tactical analysis, often discerning Quirk mechanics after a single observation. His combat stamina is exceptional, fighting through severe injuries like shattered limbs or amputation. Key battles include holding off dozens of villains single-handedly at the Unforeseen Simulation Joint, participating in the Shie Hassaikai raid, and suppressing High-End Nomus during the Paranormal Liberation War by erasing their Quirks. During the latter conflict, he prioritized maintaining Erasure to protect allies despite losing a leg and eye, stating he could not die until his students graduated as heroes. Significant relationships define his development. His long-standing friendship with Hizashi Yamada (Present Mic) dates to their U.A. student days; Hizashi coined his hero name "Eraser Head." Initial friction with All Might over teaching methods and favoritism toward Izuku Midoriya evolved into mutual respect following All Might's retirement. Among students, he mentors Hitoshi Shinso—whose Quirk resembles his own—training him in Binding Cloth, gifting him a capture weapon, and facilitating his transfer to the hero course. For Class 1-A, he maintains complex dynamics: he initially doubted Izuku Midoriya's potential but later acknowledged his growth, particularly when Izuku defended him during the Paranormal Liberation War. He recognized Katsuki Bakugo's volatile nature but defended his heroic spirit against public criticism and expressed pride in his gradual cooperation. He guided Shoto Todoroki toward trusting teammates during an exam and consoled Ochaco Uraraka after a mentor's death. His guardianship of Eri involves daily care and using Erasure to control her Rewind Quirk.