Koishi Herikawa

Age: 16
Height: 154 cm
Weight: 42 kg

She is one of Kei's close friends who also pursues a romantic relationship with Kei. Her parents own a grocery store and she often has to go to deliver food that people ordered.

Koishi has a happy-disposition to her personality and is only ever seen crying when it comes to matters that involve Kei. One of the things Ichigo would get irritated at was that Koishi would never act on her urges and in effect she waits too long, and by the time she does tell Kei her true feelings, he's already hopelessly in love with Mizuho.

In the OVA it is revealed she and Yamada have entered a sexual relationship.