Oono taught Karma Akabane during his second year at Kunugigaoka Junior High School. Like most of the main building staff, he was openly hostile and discriminatory toward Class 3-E students, looking down on them as inferior. He's remembered as contemptuous and petty—fans often note his deliberate disruption of Class 3-E during midterm exams as a particularly low moment.
His defining trait is his obsession with how others perceive him. He initially liked Karma because of his academic performance, but quickly abandoned that favoritism once he worried that Karma's reputation was dragging down his own image. It's a pretty telling moment about where his priorities actually lay.
Content compiled by AnimeList.moe from publicly available sources.
