Angels are an ancient and extremely powerful race of winged celestial beings created by God which have fought against the demon legions for eons. According to legend, it was an angel, specifically the Archangel Raziel, who created the Nephilim with the Mortal Cup and his blood. Possessing enormous power and unrivaled wisdom, Angels reside in Heaven and only set foot on Earth in times of great need or if they are ritually summoned.
The history of angels can be traced very far back to well before humankind and the Earth were born when existence itself was still young, making them the oldest race of being in existence. They were created by God to be the soldiers, guardians, caretakers and keepers of Heaven and to act as his intermediaries. Organised into various classes, they were present when the race of humans was born upon the Earth and all bowed before the humans when asked to do so by God except for one; Lucifer, who was subsequently cast out of Heaven and vilified by all angels. Initially acting as shepherds and guides for the early humans, the angels eventually took up their soldierly responsibilities when the race of demons emerged on the Earth led by Lillith, the Mother of All Demons and her mate, the fallen Lucifer. In the war that followed, the angels emerged victorious and drove the original race of demons from the Earth and into a spiritual-limbo dimension from which they could not escape but the victory was rendered hollow as legions of lesser demons began to emerge on the Earth as well as new races of hybrid beings that were the result of demonic couplings with humans and angels alike as well as the introduction of demonic diseases.
Unwilling to commit to a never-ending conflict that would wreak continuous devastation on the Earth, the angels withdrew from the mortal plane and returned to Heaven. Before leaving however, one of their number Raziel decided to give humankind a parting gift; he gave to a human three relics including a chalice, into which he poured his own blood and had the human drink it, transforming him into the first of the Nephilim, a new race of human-angel hybrids that could effectively combat the races of lesser demons and protect humankind from them. Having accepted the new status quo, the angels lost gradually lost interest in humanity over the eons and came to have a somewhat low opinion of the Earthly races in general. Not one was ever seen on Earth again until the 20th century when Valentine Morgenstern somehow managed to capture Ithuriel, the Angel of Sacrifice, and use his blood to enhance the powers of his daughter and his adopted son. Ironically it was they who discovered Valentine's secret in 2017 and managed to free Ithuriel, who returned to Heaven. Presently, no angels have been seen or heard from since.
The five Archangels are the oldest and most powerful angels of all, being created before, and separately from, the rest of their brethren. They are by far the strongest of their race, possessing near-immeasurable power, untold wisdom and are the only angels to have seen God's true form. It is they who exert operational authority over angel-kind as a whole and are respected and feared by all. They rank in the following order:
- Michael: The eldest and most powerful Archangel of them all. Described as the mightiest and the most loyal, he is the Viceroy of Heaven and is outranked only by God himself. Michael is the supreme commander of the Heavenly Host and was the guiding hand that led the angels to victory in the first demon war. It was he who personally cast his brother Lucifer out of Heaven, though the action caused him great pain and guilt.
- Lucifer: The second-oldest Archangel and the most infamous. Described as the most prideful and avaricious, he was the only angel that refused to bow down before humans and was cast out of Heaven by his elder brother Michael, left to wander the Earth as a fallen angel for eternity until he met and allied himself with Lillith. He despises humankind and was instrumental in the creation of the races of demons and by extension the Downworlders.
- Raziel: The third-oldest Archangel and least known of his brothers. Described as the wisest and most prescient, he played a pivotal role in the safeguarding of humankind from the races of lesser demons by creating the race of Shadowhunters to hold them at bay. He holds humanity in high regard but is staunchly against direct interference on the mortal plane. He has a contentious relationship with his brothers over his creation of the Nephilim which persists into the present.
- Raphael: The second-youngest Archangel and the most headstrong. Described as the most ruthless and imperious, he is a hard-line traditionalist and has a decidedly black-and-white view on the concept of good vs evil. Though he bowed to humanity, he did so reluctantly and has a very low opinion of humanity that is exceeded only by Lucifer. He views aiding lesser beings as beneath him and a waste of his power and is concerned only with maintaining the supremacy of Heaven over demon-kind.
- Gabriel: The youngest Archangel and the most unpredictable. Described as the most mischievous and idealistic, he cares for his brothers deeply and is most often caught up in preventing infighting between them. He serves primarily as the lead messenger of God and still maintains a watchful vigil over humanity to the present day, though he hides this from his brothers. Gabriel is the least inclined towards fighting but is nonetheless a highly capable warrior and is unquestioningly loyal to Heaven and his family.
All Shadowhunters have some level of angel blood in their veins, specifically that of their creator, Raziel. However, an exceptional amount of pure angel blood—Ithuriel's, as a result of experiments by Valentine Morgenstern—runs in the veins of a number of Shadowhunters, giving varied results, namely:
- Clary Fairchild was unwittingly given an exceptional amount of angel blood, particularly Ithuriel's, while in her mother's womb by Valentine. This connection with Ithuriel allows her to see and draw old runes—those not documented in the Gray Book—sent to her through visions by the angel.
- Jace Herondale was also given Ithuriel's blood, also while in his mother's womb, as part of Valentine's experiments. It gave him innate strength and skill far superior than ordinary Nephilim, along with the ability to activate runes on his and others' skin without the need of a stele. It also makes his eyes glow gold when he uses his rune-activating ability. This excess angelic blood also turned the vampire Simon Lewis into a Daylighter and protected him from the effect of the Soul-Sword.
- Jocelyn Fray was given doses of angel blood by Valentine, unwittingly giving her daughter angel blood as well. She, like Clary, also received some ability to use runes unconventionally, though in a lesser degree compared to Clary's; for example, she and Clary were both able to place—and later withdraw—three-dimensional objects within an otherwise flat surface or material, such as on drawings or paintings, but she does not have access to other runes that Clary has.