Oumi Kokoro

Renri's little sister. Prior to the story, she was hospitalized due to poor health condition. After spending some time in the hospital, she finally discharged from there and lives at Erdõs Dormitary.

She starts learning to cook from her brother, because she didn't want to become a burden for him in the dorm. To everyone's surprise, Kokoro is a fast learner in cooking. And in a short time, Renri entrusted her in making the meals for the dorm's tenants.