Seiji is a proud and dignified individual who values Shiketsu's teachings about obligation and dignity above all else. He often stands with his arms behind his back and uses eloquent language when speaking, which causes people to refer to him as "Senpai". Seiji believes all heroes should be dignified and vulgar individuals are unworthy of becoming heroes. He believes this so strongly that he prioritized incapacitating unworthy students during the hero licensing exam over actually trying to pas