Asmodeus, or Ashmadai (from the Hebrew), was one of the fallen angels, or demons that existed in the djinn world. The Shorter Baghdad Rules described him as having three heads- that of a bull, a ram, and a brutal looking ogre. The creature had a reptilian tail and feet of a giant black rooster. John Gaunt and Philippa Gaunt saw him outside their train window when meeting Izaak Balayaga. When Izaak arrived, he claimed that Asmodeus was chasing him for the Solomon's Grimoire.
According to Izaak, Asmodeus had long been jealous ofSolomon's great power and influence. When Solomon was the king of Israel he stole his ring of power and impersonated him in his own palace. One of Solomon's thousand wives noticed that he had demon tracks and stole the ring and gave it back to Solomon.
But as he was pretending to be Solomon, he discovered the book he was writing, the Solomon's Grimoire. It contained his wisdom and how one could gain power over djinn, angels, mundanes, and humans. Since then, Asmodeus has been trying to retrieve the book.
Asmodeus is also known as Ashmadai (Ashmedai, Hebrew) Asmodai (also Hebrew,) *Saturn (Saturnus, Latin origin) Marcolf (Marolf, Chiefly German), Bertholdo (Italian origin), Chammaday, and lastly, William Shakespeare abbreviated Asmodeus' name to Modo.
*It is worth observing that the Roman god Saturn is often viewed as the equivalent of the Greek titan Kronos, "He who devoured his children" (the six original gods and goddesses of the Greek pantheon.) It raises the question whether or not Asmodeus and Kronos were viewed as the same deity.