Higanbana

Higanbana is the third-highest ranking youkai in the school, also known as the "Dancing Higanbana". She is a girl who takes the form of a Western doll that sits in the school infirmary and, according to her associated legend, dances on its own at night. She is the youkai who directly offers Marie to become Mesomeso, and treats her as her personal assistant. She regularly torments cruel or weak-willed students, and is depicted as either an antagonist if she targets a story's hero, or as an antihero if she targets a villain.

Note: Her name is Higanbana. Odoru is translated to Dancing. She is known as the 'Dancing Higanbana.' Thus the name Odoru Higanbana, but it's not her actual name.