Otonashi Kushina

A girl who’s constantly bright and cheery. Her home’s far away, so she’s currently living in the school dorms. On occasions where she gets mad or upset, she’ll sometimes revert to her native dialect.

Presumably thanks to being Kanae Otonashi’s cousin, they get along well. Her love for manga and anime also seems to have made her friendly with Iori. For some reason, she trusts the protagonist to an unusual extent.