Yoriko Yasuzumi

Yoriko Yasuzumi is introverted, bookish, and fascinated with the occult. One night, with Lilica's help, she decided to try to summon a low-level demon servant for herself. As a prank, Lilica re-drew the magic circle, and Yoriko summoned Mike, the self-proclaimed “Demon King”. A contract was formed between the two of them, and now she is unable to part with him. Her Arcana, Dieu Mort (Evil), was formerly a man sentenced to be executed known as the "God of Death." She is voiced by Yui Itsuki.

Story
Yoriko's introverted and bookish, but she's overly fascinated with the occult. One night, with Lilica's help, she decided to try and summon a low-level demon servant for herself. Before starting the ritual however, she chickens out and runs to the bathroom. So while Yoriko's busy splashing cold water on her face and talking to herself in the mirror for encouragement, Lilica (being the no-good prankster she is) re-draws the magic circle's incantation. When Yoriko returned and began the ritual, what she summoned instead was some self-proclaimed “Demon King” who goes by the name of "Mike." The contract was formed between the two of them that night, and now she is unable to part with her unusually-shaped companion.

Trivia

 * Yoriko has three of her alternate colors make her look like Chitose Akiyama, Lambda-11 and Tomoko Hoshina.