Eriru has multiple personality disorders.
She wears a brown tank-top that covers only her chest, a brown skirt, a yellow bandanna on her head and purple high-heels. She has bat-like ears, brown hair, pink blush, and dark brown wings. The color and shape of her eyes depends on what phase she's in.
In her Water Demon Form, Eriru attacks with black, wavy arrows. She can also manipulate objects with her shadow-like powers and create whirlwinds with her spinning. The rag or bandanna on her head protects her cat-like ears from hearing a mermaid's song. However, it only works in Episode/Chapter 2, though, because only one mermaid, Lucia, sang to her, and one mermaid's voice probably isn't loud enough. When two or three or more gather though, her rag probably won't make much of a difference, and she has to resort to using sound systems to block out the music and hurt the mermaids.
- Eriru is from the Dark Beauty Lovers.