Kei Mizutani (水谷 恵,Mizutani Kei?) is a second year high school student and a main character in Blood School.
Kei is a shorter than average male with shoulder length orange hair, and vibrant, dark reddish-brown eyes. He wears the female school uniform consisting of a yellow blazer and pleated skirt, a white, long-sleeved blouse, a red ribbon, and brown shoes.
Kei is a bright, bubbly boy who gets easily frightened. He seems to have a crush on Kyoko and because of this he's very protective of her and Tatsuya and would put himself in harms way to save her.
Kei may be based off of Miyu Shinohara, due to both being biological males that wear female clothing, having crushes on the main character and their roles looking after the main characters younger sibling.
The kanji for Kei's given name can be read as 'Megumi', a common Japanese female name.