**Height:** 143 cm
Saiko Yonebayashi is a Rank 3 Ghoul Investigator, a Quinx, and a member of the Quinx Squad. She dislikes having to work, as she prefers having a peaceful, happy-go-lucky and carefree life by playing video games and eating junk food excessively. Saiko often oversleeps, which earns her the absence from most missions. While not trying to reduce it, she is apparently embarrassed about her weight, humorously covering it during her introduction.
She is excessively lazy to the point of being a hikikomori, unable to remove herself from her room without the intervention and often force of others, even jeopardizing her occupation. Saiko is also depicted as greedy, and heavily involved in her video games to the point of escapism.
