Kazuya Watari

The male character of the show. The ever so lucky or perhaps unlucky guy who discovers the identities and secrets of different kinds of girls throughout the series and ends up with living with all of them. In the beginning, he discovered the identity of Guardian Hearts Hina, and so to keep it secret he had no choice but to let her live with him. The rest is the same for all of the girls who followed afterwards.

(Source: Wikipedia)