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. He is somewhat of a masochist and is attracted to Mikari.
He is a kind gentleman that treats Mikari with full respect and manages to put up with her bratty and sadistic attitude.
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 Mikari's parents wish to protect her.
- His hobbies consist of housework assistance, mental arithmetic, cooking, exercising and massage.
- He likes hot springs and dislikes Coriande.
- His favorite celebrity is Yuriko Yoshitaka.
- His birthday is on December 24th.
- His horoscope is Capricorn, along with Mikari and Kaname Asagiri.