For a looser approach to the witch-hunter, using the alternative class rules I've been posting about, I'd use a Hybrid Fighter/Cleric with a background in "witch-hunter". Possible variants include mixing Cleric with other classes:
- Van Helsing would be a mixed Cleric/Magic-User;
- Solomon Kane would be a mixed Fighter/Cleric;
- Matthew Hopkins in the film Witchfinder General (aka The Conqueror Worm) would be a mixed Trickster/Cleric (assuming he has supernatural powers at all,) using the subterfuge bonus for clever tricks to bolster his arguments;
- another possibility for a roguish but not necessarily evil witch-hunter would be a mixed Charmer/Cleric, or for a non-powered Gilliamesque Brothers Grimm version, mixed Charmer/Trickster.