A high school freshman who resides at the Kawai Complex as one of the tenants. After graduating from middle school, he hoped to have a life where he didn't have to encounter any weird people. However, much to his surprise, his co-tenants end up being a bunch of odd individuals. Usa chooses to stay at the Kawai Complex though, due to the fact that the girl he has a crush on, Ritsu Kawai, happens to also be a tenant at the Kawai Complex. Unfortunately, the other tenants take advantage of this by constantly teasing Usa.