Youko Kishi, also known as Yoko Kishi, is a Japanese female character. She possesses distinctive violet hair and brown eyes, standing 160 cm tall and weighing 42 kg, with body measurements of 80-57-82. Her blood type is B and she is a Libra. Working as a student librarian, Youko defies the typical quiet bookworm stereotype, instead exhibiting a lively personality alongside her friends Mizuki, Nagisa, and Karami. Her hobbies include reading pure literature and playing the piano.

Romantically, Youko had relationships with both Yuuichi and Kotaro at different times. Following a sexual encounter with Kotaro, she became pregnant. She chose to keep this pregnancy a secret from him. Her condition remained hidden until it was discovered by a teacher nurse and Yuuichi.