Necromancy

Necromancy is a form of black magic, that is utilized by the enigmatic being known as Abaddon Nightwalker. This art, allows its practitioner to conjure vile spirits, commune with and command the dead, even raise them into various powerful undead monsters. According to Abaddon, this form of magic is considered Divine Magic, in that he draws his power through faith in the goddess of death ---Nyx.

Description
Necromancy is a broad category of magic, that allows the practitioner to utilize various black arts to manipulate the souls of the living and the dead. It is an incredibly complex art, and can be first identified by its use of ritualistic fetishes; necromancy makes heavy use of magic circles, sigils, and various symbols in order to draw the necessary connection to power any given spell. Abaddon being a "Holy Knight" of his Goddess, uses his holy symbols to draw a connection to his goddess using his faith as the bridge. Through this, he is able to draw upon terrible powers of life and death. Using this form of magic, a practitioner can sap the life force out of living creatures, empower themselves through pain, death and corruption.

Necromancy is a form of magic that draws its power from negative energy a source of power existing in an "outer realm" beyond the fringes of the universe, that seeps into our world. He calls it the source of all evil magic. Using necromancy, a practitioner is capable of summoning forth negative energy as a means of attack and defense. They are also able to conjure the spirits of the dead, typically for information, at other times to be used as ghostly scouts, or to haunt and terrorize a populace. These spirits can be also implanted into organic matter; corpses and such, animating them to create powerful, sentient undead monsters, with unique skills and abilities.

Faith Based Power
While some necromancy can be cast as any other magic, the necromancy Abaddon performs is very different, for its principle source of power is not through ones own magical energy, but through faith. This is a stark contrast to other forms of magic, which are considered largely internal. Abaddon is a Paladin, a man wholly devoted to the cause of Nyx, it is his conviction, his empathy to her ideals that allow him to draw strength from her as her champion. As such much of his magic will often require various prayers in her name, including certain rituals and doctrines he must abide by to remain devout.

More to come...

Goddess of Death
Nyx, as Abaddon refers to her is the Goddess of Death, and he is her Paladin, a champion of her cause. Beyond that, there is very little information regarding her origins, and what her true aims appear to be. She apparently acts as the master of Abaddon, directing him and granting him blessing, including much of his unique powers.

Trivia
Necromancy is heavily based on the magic of the same name in Dungeons and Dragons, as well as Pathfinder.