Tetsukasa Tsuchikiyose is a high school student who holds the position of student council president. He shares a marriage with the twin creatures Roku and Nana, unique one-eyed, one-winged beings whose diet consists solely of food additives. This marriage entails cohabitation and the sharing of domestic responsibilities between Tetsukasa and both entities. Physically, he presents as a teenage male with brown eyes and brown hair cut to neck length. Tetsukasa participates in school activities alongside peers similarly involved in interspecies marital arrangements.