Bifrons
A demon of monstrous guise who, according to Johan
Weyer, often took the form of a man well versed in astrology
and planetary influences. He excels in geometry, is acquainted
with the virtues of herbs, precious stones, and plants, and, it is
said, he is able to transport corpses from one place to another.
He also lights the strange corpse lights above the tombs of the
dead. Twenty-six of the infernal regions obey his commands.
Sources
Weyer, Johannes. Witches, Devils, and Doctors in the Renaissance
Johann Weyer, De Praestigiis. Edited by George Mora.
Binghamton, N.Y. Medieval and Renaissance Texts and
Studies, 1991.