Izumi Ishiguro

Koyuki's childhood friend, he eventually was left to choose between her and Maho, though by the time he reached his decision, the two girls also reached one of their own, luckily a similar conclusion. In a way, Izumi is the polar opposite of Maho in that she's rather sweet and kind to Koyuki for the most part. She deeply cares about Koyuki as they were childhood friends and thus gains feelings for him when she starts to see him grow into a more confident person.