Hayate is Kohaku's best friend. When they were young, Kohaku accidentally turned him into a frog with a jutsu. On every full moon he turns human for a day. He was in love with Kohaku but in volume 10, he realizes he has fallen in love with Rurijo after he (in his frog form) sees her bathing. They become good friends and Rurijo sprinkles moon water on him to make him permanently human.
"Hayate" is a common name for Japanese males.
Hayate's soul symbol is unknown.