He originally was the Roman god, Janus.
In ancient Roman religion and myth, Janus (Latin: Ianus) is the god of beginnings and transitions, thence also of gates, doors, passages, endings and time. He is usually depicted as having two faces, since he looks to the future and to the past. The Romans named the month of January (Ianuarius) in his honor.
Janus presided over the beginning and ending of conflict, and hence war and peace. The doors of his temple were open in time of war, and closed to mark the peace. As a god of transitions, he had functions pertaining to birth and to journeys and exchange, and in his association with Portunus, a similar harbor and gateway god, he was concerned with travelling, trading and shipping.
Janus had no flamen or specialized priest (sacerdos) assigned to him, but the King of the Sacred Rites (rex sacrorum) himself carried out his ceremonies. Janus had a ubiquitous presence in religious ceremonies throughout the year, and was ritually invoked at the beginning of each one, regardless of the main deity honored on any particular occasion.
The ancient Greeks had no equivalent to Janus, whom the Romans claimed as distinctively their own. Modern scholars, however, have identified analogous figures in the pantheons of the Near East. His name in Greek is 'Ιανός (Ianós).
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 Jinnestan'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