Yuiyui is a beautiful middle-aged woman with straight, dark hair which falls down to her waist. She has the characteristic black hair and red eyes of a Crimson Demon, but with a tired, calm look as opposed to the more excited members of her clan. She wears a long, sleeveless dress and armbands on her forearms.
She cares greatly for her family and wants the best, evidenced both in how she works hard to support them financially, and how, when she learned that Megumin values Kazuma, she wholeheartedly supported their relationship despite believing he is still under a burden of massive debt. Yuiyui reveals a cunning nature upon learning Kazuma is rich, quickly putting the two meddlers in the room (her husband and Darkness) to sleep and trying to force both Kazuma and Megumin into a situation where he would have to "take responsibility."
Advanced Magic: Like all Crimson Demons adults, Yuiyui is an Archmage, demonstrated by how she easily put the aforementioned Hyoizaburoo and Darkness to sleep
Tranquilizing Magic: She uses sleep magic on Darkness and her husband and even on her own daughter Megumin.