Yamabuki Aoi

Haruki's childhood friend and Wataru's younger sister. Due to her looks and outgoing personality, she's really popular at school. She has been confessed to a lot, but she turns them all down, not to mention she doesn't completely realize what love is. Aoi always put others first and is not really honest with herself. She often hands out all kinds of charms to Haruki in order to protect him from his misfortunes.

Edited from Mayoi's review