Bakudan Komusume Rin!

Rin Kazamori is a girl who lives to fight. She takes on any challengers, and has only been defeated but once. She fights to find the one man who was able to best her, so that she may marry him, but she knows not his identity...she knows him only by the twinkle in his eye, and the mark on his buttocks. However, Rin's quest to find her one true love takes her to places she never imagined even existed...