Originally an angel who joined Lucifer's rebellion against God during his war in Heaven, Asmodeus was cast out like Lucifer and others, Asmodeus degenerated into a demon and came to rule a subsection of the nether realm Hell. He also mated with fellow outcast Lilith, parenting many demonic offspring, though most were slain by agents of Heaven.
In recent years, seeking to restore his waning power over humanity, Asmodeus used his Netherflame to identify the Ghost Rider as a powerful demon he could use to terrorize Earth. Asmodeus dispatched the she-witch Tabicantra to destroy the humanity within the Ghost Rider (Johnny Blaze) so Asmodeus could enslave him, but Tabicantra fell in love with Blaze and used her own life force to save him from V'Zarr-Than and Asmodeus' other demons. Asmodeus later had another demon, Rhz'arr, abducts Blaze and brings him to Asmodeus' realm where he attempted a ritual to eradicate Ghost Riders last vestiges of humanity, but Ghost Rider Broke free and attacked with hellfire, forcing Asmodeus to send Ghost Rider back to Earth. Asmodeus next gambled with fellowed Hell-Lord Mephisto for control of the Ghost Rider. The Ghost Rider demon self, Zarathos, was split from Blaze and the two ran a gauntlet of Asmodeus design to return to Earth. When Asmodeus lost the contest by failing to prevent their escape from Hell, Mephisto imposed a "small penalty" by incinerating Asmodeus.
Years later possibly after Franklin Richards had temporarily dispersed Mephisto; Asmodeus regained power and retook his realm of Hell, awakening his minions from their slumber. To initiate his campaign of terror, Asmodeus facilitated Dracula's resurrection with the aid of human pawn Professor Gregor Smirnoff. Asmodeus aided Smirnoff in granting Dracula vast power via sacrifice of Smirnoff's cult, the Belonging.
Note: Asmodeus' name and variations thereof have been used by many demons and other beings over the years, it is believed that Asmodiar, a Hell-ruling demon who sent his son, Beliar, to assault 6th century Camelot, was actually Asmodeus himself. Merlin decapitated Asmodiar using Beliar's sword, though this was a temporary setback. An extradimensional amorphous demon named Asmodeus marked twins, Angela and Joshua Farkas, children of the Enclave cult members it had saved from Nazis years before. The Enclave last summoned that Asmodeus to earth to mate with Angela, after which Joshua (now the Dimensional Man) drove Asmodeus back to its realm. The long-legged bird demon Azmodeus served as adviser and familiar to Mephistos' pawn Master Pandemonium; Mephisto may have restored the true Asmodeus and consigned him to his lowly position. This may have been Asmodeus' first step towards regaining his power and his realm.
Check out others who have used the name "Asmodeus" at the Disambiguation Page