Bifrons

Bifrons (also Bifrovs, Bifröus, Bifronze) is a demon, Count of Hell, with six legions of demons under his command. He appears as a monster, but then changes his shape into that of a man.

He teaches sciences and arts, the virtues of the gems and woods, herbs, and changes corpses from their original grave into other places, sometimes putting magick lights on the graves that seem candles.