Looking for unique romance

Hey guys, I'm looking for a romance anime/manga (preferably shounen) that has a unique girl as the heroine or one of the important characters. By unique I mean like they express their love differently to the norm, they're yandere, sadistic or just weird... in some way..

Examples are like Noe from true tears, Eriko from KimiKiss or Senjougahara from Bakemonogatari.

THANKS IN ADVANCE :)