Byleth, an illustration from the "Dictionnaire Infernal" by Jacques Collin de Plancy.
In demonology, Beleth also spelled Bilet, Bileth, Byleth and Bilith is a mighty and terrible king of Hell, who has eighty-five legions of demons under his command. He rides a pale horse, and all kinds of music is heard before him, according to most authors on demonology and the most known grimoires. According to Pseudomonarchia DaemonumHam, Noah's son, was the first in invoking him after the flood, and wrote a book on Mathematics with his help.
When appearing he looks very fierce to frighten the conjurer or to see if he is courageous. The conjurer must be brave, and holding a hazel wand in his hand must draw a triangle by striking towards the South, East, and upwards, then commanding Beleth into it by means of some conjurations.
If he does not obey, the conjurer must rehearse all threatens the conjurations said and then Beleth will obey and do all that he is commanded. But the conjurer must be respectful and do homage unto Beleth due to his rank, and hold a silver ring in the middle finger of the left hand against his face, as it is the use of hellish kings and princes before Amaymon.
Beleth gives all the love of men and women he is commanded until the conjurer is satisfied.