Kensaku Ono

Ono keeps his dark brown hair short and has narrow, thin eyes. His skin is lightly tanned, and he is usually shown wearing a stern, serious expression.

In the mold of much of the main-building faculty, Ono is hostile and harsh, at times aiming that cruelty at Class E. He is fundamentally indifferent to his students, caring nothing for their welfare or conduct unless it happens to burnish his standing as a supposedly successful teacher. Even so, despite backing Gakuho Asano's education policy, he is visibly rattled when the chairman moves to inflate the final exams to college-level difficulty.

Ono once taught Karma Akabane and, thanks to the boy's strong grades, played the supportive mentor. That mask fell away after Karma beat up a classmate for bullying a Class E student; Ono turned on him, insisting he had no business protecting worthless E-class trash at the expense of a promising pupil. A furious Karma trashed his office, and the incident birthed a lasting contempt for teachers that lingered until Korosensei later saved him from a fatal fall. Ono had little patience for Nagisa Shiota either, branding him an unteachable brat and blaming him for the worst teaching review of his career. He seemed pleased to see Nagisa transferred to Class 3-E, and the two are not shown crossing paths afterward.