Rena is Erika's younger cousin who is a middle school year 3 student. Her grades weren't too good, so Erika and Erika's mom asked if Kyouya could help her study which he agreed too. Rena is quite obsessed with wanting to be and appear like an adult, so she randomly starts dating a guy just so she wouldn't lose to Erika (since she does have a boyfriend). One day things get quite troublesome between Rena and her boyfriend and Kyouya who was passing by saw them and helped Rena. Since then Rena fell in love with Kyouya. After a while she cofesses to him, but he rejects her. Later on she also starts going to the same school as Erika and Kyouya.