Koichi Sumita

A very shy person who likes Katie, and has confessed to her. Once, because of Azumi, Hanzo, and Sasuke, he and Katie accidentally kissed. He is good at sports and has two younger twin sisters. Like Mirumo, he likes chocolates, and he also loves Kumocho. He always supports Katie. At the end of the season, he is dating Haruka Moroshita. (First appearance: episode 151)

His muglox partner is Papii. She try her best to help Sumita get closer with Katie while didn't know that Katie has a crush on Dylan.