Yuki holds the appearance of a stereotypical butler in anime and manga. He has white hair that's balding as well as bushy eyebrows and a mustache. He wears a plain black suit to go with his attire.
Yuki is a kind gentleman that treats Mikari Izumigamine with full respect and manages to put up with her bratty and sadistic attitude. He is somewhat of a masochist and is attracted to Mikari.
When he and Mikari were being held captive by a serial killer in chapter 52, Mikari provoked the killer causing him to put her in a gun point, he immediately tackled the killer, in fear of disobeying Mr. Izumigamine & Mrs. Izumigamine. During Mr. Izumigamine's last breath, he tells Yuki to protect Mikari, which Yuki agrees.
- His hobbies consist of housework assistance, mental arithmetic, cooking, exercising and massage.