Christine's 3-year-old cousin. Momoka often drives along in her tiny toy tricycle and befriends Ruu, declaring that he is her boyfriend and that they are in a close relationship. Momoka has an odd grudge against Miyu, often calling her Madam or obā-chan, a title used for an elderly woman or grandmother, which in result infuriates Miyu all the time. Momoka learns Miyu and Kanata's secret about having two aliens in their house in the episode "Momoka's Passport", where she saw Ruu fly in the sky in order to get the balloon.