He is Tensai's assistant, where he and the latter maintains a sort of Sherlock Holmes and John Watson kind of relationship. Though, he may look like a girl, he is actually a boy, he along with Tensai transfers to Juugo's school where they are also the latter's classmate after their brief visitation at the latter's apartment where they also met Nanana. He also becomes a member of the "Adventure Club" since he goes where Tensai goes.

(Source: AniLinkz)