|“||There's always a price, with my father.||”|
Asmodeus is a Greater Demon, particularly a Prince of Hell and a fallen angel. He is also the father of the warlock Magnus Bane who, because of Asmodeus' influence and power, is often let off by other demons.
Prince of Hell
During the sixteenth century, a seeress prophesized that his addiction to taking human memories and emotions would be his undoing, though he was never troubled by this, unbothered by human superstition.
Asmodeus supposedly has many children: he has demon children in Edom called asmodei, as well as warlock offspring on Earth. By 2007, most of his warlock children have died, one reason being that, usually after many years of living, he had already claimed their immortality, using their lives to fuel his realm. Others died due to the instability of being a powerful warlock child of a Greater Demon unable to truly thrive in other worlds.
Magnus Bane is a notable offspring of his, through a woman whom he tricked into believing he was her husband. In the early 1600s, Asmodeus paid a visit to a young Magnus as he was being drowned by his stepfather in Indonesia. Asmodeus whispered a spell to Magnus which enabled him to save himself from drowning by becoming a column of fire, burning his stepfather to death in the process. Asmodeus then told his son to go and make himself worthy and assured him that he may come back to claim him one day.
Asmodeus once again appeared to Magnus approximately two centuries later, summoned unintentionally by the actions and worship of the Crimson Hand, a mock cult started by Magnus that did good deeds in Asmodeus's name. Pleased, Asmodeus decided to take control of the cult, assuring Magnus that he would put all his new followers to good use, and removed his memories of both the cult and Asmodeus's reappearance.
In 2007, during an attempt by the Crimson Hand's new leader Shinyun Jung to sacrifice Magnus to his father, Asmodeus was summoned once again to Earth by the collective wishes of his assembled followers. He attempted to convince Magnus to kill Shinyun and sacrifice her, thereby reclaiming the Crimson Hand for himself and allowing Asmodeus to cross over fully into the world. He also expressed his pride for Magnus, and his wish to see his son raised up in glory.
When Magnus refused to accept his father's offer, Asmodeus turned his attention to Shinyun, promising her all that Magnus had refused if she killed him. Magnus was saved by the Shadowhunter Alec Lightwood and the two used their combined strength to break the ritual pentagram and banish Asmodeus, who made a last attempt to claim his son by pulling him into an abyss but failed.
The Dark War
Lilith's "son", Sebastian Morgenstern, used Edom as his and his army's base and retreat as it is undetectable by the Nephilim. Sebastian's followers acknowledged their power and often dedicated their massacres, presenting the souls or their captures as sacrifices, to Asmodeus and Lilith, the rulers of Edom.
When Sebastian sent his kidnapped Downworlder representatives to his realm, Asmodeus gained control over Magnus' magic and will. With this, Asmodeus weakened Magnus in hopes of making him call on him for help, an urge which Magnus fought.
Before his death, Sebastian destroyed the pathways between Edom and the Shadowhunters' dimension. Desperate, Magnus called upon his father using an inverted version of the Lord's Prayer for his friends to ask him to send them back to their dimension. After some small talk, he demonstrated his power by transporting Luke, Jocelyn, and Jonathan's body back to Alicante.
Knowing what Asmodeus wanted, Magnus offered to trade his immortality for the safe return of his friends. However, Simon Lewis offered to give his own immortality instead of Magnus'. Pleased to receive his Daylighter power and his immortality, Asmodeus gladly accepted Simon's; though because of Simon's short life, in comparison to Magnus' hundreds of years, he also insisted on taking not only his immortality but also his memories of the Shadow World, as well as his friends and families', promising to give Simon his mundane life back instead of leaving him the undead corpse of a vampire he was.
Asmodeus appears as a shifting patch of shadow before evolving out of the darkness as a tall man with a human face, pale skin seemingly stretched and taut over bone. He has sharp, pointed teeth and gold-green eyes that have slit pupils like a cat's which Magnus inherited.
On the two known occasions when he was summoned, he was dressed smartly in a pure white suit with silver cuff links, buttons carved in the shape of flies, and a coronet of barbed wire on his head.
- Jace Herondale once mentioned that he was a general of Hell's army.
- In 1929, after Aldous Nix opened a Portal to Hell while in Magnus's presence, a demon spoke to Magnus and claimed to be his father. He was uncertain about the demon's identity at the time, but Magnus eventually found out and must have contacted him some time after this.
- Chain of Gold (mentioned only)
- The Rise of the Hotel Dumort
- What to Buy the Shadowhunter Who Has Everything (mentioned only)
- The Red Scrolls of Magic
- City of Lost Souls (first mention) (chapter 11)
- City of Heavenly Fire (first appearance) (chapter 23)
- Born to Endless Night (mentioned only)
- Lady Midnight (mentioned only)
- Queen of Air and Darkness (mentioned only)