柴谷 栖

"Nin-nin!"

Sumika is a friendly girl, the only first-year in the group. Without no concern for the age difference, she is getting along splendidly with Yasunari, often exchanging comical dialogue with him.

Truth be told, Yasunari does not remember when it was that he first met her, although he is nonchalant about it and hangs out with her like they have known each other forever.