Katsumi is the chef at the Twilight Manor. He first appears in story 8 of the manga and is one of the few individuals who call Yuki by "-san" instead of -"sama," without him asking. He studying culinary arts in Italy and is very enthusiastic when it comes to his cooking.
He doesn’t take it very well when someone criticizes his food, or, at the very least, HINTS at eating anything else than what he’s just cooked. He is called Ka-chan by Tachibana.