Yuuka Amato

The Student Council Accountant (treasurer). She is also a ninja. Yuka appears to be carefree most of the time. However, she is very cunning, mostly encouraging activities of the Maken-ki that involve some kind of other work that needs to be done. The most obvious of these actions is the "match" between Venus and Maken-ki, where the players use broomsticks and soap while playing in the pool. She is close friends with Furan and likes to tease her.

Yuka is also the younger sister of Takeru's homeroom teacher Tomiko Amado.

(Source: Wikipedia)