Aqua

A girl of many secrets who keeps showing up around Youichi. She too bears the same name as one of the twelve zodiac signs. She acts in a mysterious way, alluding to certain things without revealing key details. However, it appears she knows Aries somehow...

Aqua is distant and aloof around others, unaware of the fact that her facial expression often betrays her true feelings.

"It's because I'm a failure."

(Source: MangaGamer)