Kensaku Ono

Kensaku Ōno is the homeroom teacher of Class 3-D in Kunugigaoka Junior High School and the former teacher of Nagisa Shiota and Karma Akabane.

Appearance
Ōno has short dark hair and thin-shaped eyes.

Personality
Ōno is antagonistic and cruel, occasionally towards Class E.

Karma Akabane
Karma is a former student of Ōno's. At first, Ōno acted friendly and supported Karma due to his good grades. However, after Karma beat up a classmate for bullying an E Class student, Ōno's true nature was revealed as he betrayed him. Karma has since stated that he's dead to him and it was heavily implied that Karma wrecked his office.

Nagisa Shiota
Ōno showed very little patience towards Nagisa and even called him an "unteachable brat". According to him, he got the worst teacher's review of his career because of Nagisa. He seemed happy upon Nagisa's transfer to Class 3-E but the two haven't been seen interacting since.

Quotes
(to Karma Akabane) "Are you out of your mind or just stupid?!"

(to Gakuho Asano) "Wait, all this just for the math portion of the exam?"