Mere

Mero is a mermaid. She is slightly overweight but very attractive. She can switch between human and mermaid forms.

An energetic mermaid that loves singing and eating fish. She can't swim in her human form for some reason. Blue hair and blue eyes.

Magic Potion: Used to use one to turn her mermaid tail into legs, but gets by with maca extract in the human world. She has to drink one every five hours or the transformation wears off.
Mind-Control Music: Inadvertently causes Naoe to hallucinate and be hypnotized from her singing during karaoke. Everyone else there was magic-resistant, so only Naoe was affected.
Shark-Toothed Humanoid: She has a mouth full of sharp teeth.
Troll: She likes to make the other girls freak out with ghost stories or making Elfuda think she ate her eggs.