Supernatural

FL reincarnates into a european-style world (1st life she was in eastern Asia) and continues her life to deal with ghosts for money.

MLs are all demons feeding off a specific human sin. FL is immune to their charming powers and helping(?) ML with having to stomach the sight of blood.

FL has some sort of power, might be a vamp as she drinks blood. Her only childhood friend believed in her and trusted in her but he was killed by the village as they saw his bite mark and staked him. FL now in a high school (seems like there are 2 campuses, one for weres, one for vamps).