It was a yaoi manga and some of my memory is foggy but I think both of them had long hair (if not, then at least one of them did). One guy had black hair and the other had white hair. One of them was a vampire/demon while the other guy was a human hunter, and is supposed to kill the vampire/demon. They were wearing some traditional Japanese clothes and they were doing it in a shrine. I think there was only about 3-4 chapters. In the last chapter or something, other hunters came to kill the both of them, so the vampire turned the human into a vampire as well so they could be run away and live together forever.

Dia Game...?