Yumiko is a hot-headed magician who met Koyomi in the past. She uses ancient magic and is related to a powerful magician (her grandfather). She treats people as if she is their superior. She breaks things when she is angry.

A natural-born mage, she has purple eyes and silver hair. She is a quick-learner at magic, she can see a complex spell and repeat it perfectly without practicing. She had a staff and a spellbook left to her by her great-grandfather, and usually wears white. She was often teased at elementary school and stared at in public because of her doll-like appearance.