Korekiyo is a tall, slim student with rather pale skin and long ocean green hair. His hair is stated to follow an archaic image of beauty and it "puts his female colleagues to shame". He has narrowed yellow eyes, and his mouth is covered by a sage green mask, covering his mouth and neck, with a zipper where his mouth would be, giving him a sinister and mysterious appearance. Korekiyo is aloof and somewhat disturbing, but he is also very cool-headed and intelligent.