I have one word: pe.do.phi.li.a, this shit is so wrong on so many levels, first of all she's 15 and he's 26, secondly he's been in love with her for what seems like some time which means he "fell in love" when she wasn't even 15, when she was a CHILD (not that she isn't now, although she's more of a teenager)
Ojou to Banken-kun