Akane Komoto, despite her youthful appearance, is a 1,000+ year old demon who secretly runs the school. She is capable of transforming herself and others around her, as well as multiplying herself. 

She has child-like behavior. Though rarely ever seen by the normal students, she often causes mischief for Asahi and his friends, and has a weakness for sweets and/ or other junk food. Akane is possibly the most powerful character in the series as she is capable of destroying the world or granting the wishes of others on a whim.

I want a Monica Rial-ish type voice for her. but if you have a different voice for her that's fine too.