In Christian demonology, Bifrons is the guardian of the corpse way.
In Roman mythology, Janus (or Ianus) was the god of gates, doors, doorways, beginnings, and endings.
Jointly with the evil Bune, Bifrons is in charge of moving the bodies from one grave to another, while hellish Murmur takes over the souls. Accordingly, Bifrons has 26 legions of Hell's army under his command, and is the 46th spirit of the 72 Solomon imprisoned in a brass vessel.
Bifrons is a demon of monstrous guise with two faces who often takes the form of a man well versed in astrology and planetary influences, excelling as well in geometry, herbology, mineralogy and botany.
Bifrons teachings include astrology, maths, medecine by plants and magic stones. He is of great help for necromancians
Bifrons is seene in the similitude of a monster, when he taketh the image of a man, he maketh one woonderfull cunning in astrologie, absolutelie declaring the mansions of the planets, he dooth the like in geometrie, and other admesurements, he perfectlie understandeth the strength and vertue of hearbs, pretious stones, and woods, he changeth dead bodies from place to place, he seemeth to light candles upon the sepulchres of the dead, and hath under him six and twentie legions.Pseudomonarchia daemonum - Johann Wier (1583)
The Forty-sixth Spirit is called Bifrons, or Bifrous, or Bifrovs. He is an Earl, and appeareth in the Form of a Monster; but after a while, at the Command of the Exorcist, he putteth on the shape of a Man. His Office is to make one knowing in Astrology, Geometry, and other Arts and Sciences. He teacheth the Virtues of Precious Stones and Woods. He changeth Dead Bodies, and putteth them in another place; also he lighteth seeming Candles upon the Graves of the Dead. He hath under his Command 6 Legions of Spirits. His Seal is this, which he will own and submit unto, etc.Goetia - S. L. MacGregor Mathers (1904)