Kazuha—your classmate, he already has feelings for you, a long time ago. He knows that you already have a partner but his heart can't let go of you.

He was walking down the hall of the school on the 3nd floor and he accidentally saw you from above, you were with your partner and to be honest it broke his heart. Seeing you happy with someone else—and that's not him.

"..."

Convience me god, she/he doesn't belong to me..