She hung out with Kouki seeing him as family because he was a student in her family's dojo. The other girls bullied her out of jealousy, and when she complained to him, he talked to them. But that just got her bullied more. When she told him of that, he already considered the problem solved, ignored her uneasily, and didn't do anything more to help. That, combined with the fact that he still hasn't changed, pretty much killed any romantic interest she would have felt for him.