A beautiful girl in Yuuta's class. Shinka is Yuuta's classmate and class representative, who is also a cheerleader. One of the most popular girls in the class due to her looks, she is generally thought of a kind and gentle girl.
She too suffered a case of eighth-grader syndrome, going by the name of Forest Summer. Like Yuuta, she chose a school that none of her former classmates were going to so she could escape from her embarrassing past. When she is with Yuuta, Rikka, and the others in the clubroom, her usual happy, sweet demeanor fades and she is blunt, edgy, and tends to fight with Dekomori quite a lot. This is because Dekomori admires Forest Summer (and does not believe Shinka is actually Forest Summer, constantly referring to Shinka as "fake Forest Summer") and has numerous copies of books, consisting of documents that Forest Summer had written, titled Mabinogion. Shinka seeks to destroy every last trace of her past, and Dekomori is a barrier against this, causing frequent fights between them.