Dark magic
Magic that is granted by utilizing the power of demons.
Demonic
The use of dark magic is normally accompanied by purplish-black shadows and fire surrounding the user.
As an inherently evil magic, dark magic is used to hurt, sabotage, and destroy opponents with either overwhelming force, or slow ruin.
Defense
Shape-shifting
Potion-making
Weapon-enchanting
Seeing spirits
Ability to understand creatures
Offense
Demon summoning
Negative status effects such as poisoning, fitful sleep, etc.
Instant death techniques
Stealing souls
Damaging spirits
Curse-casting
Dark magic is aligned with demons, which are immortal beings that stand in opposition to the Divine.
Those most efficient with dark magic can utilize many spells without cost, but many high-level spells, such as summoning, require a blood sacrifice of either your own or someone else's. Also, because dark magic is an evil magic, it takes it's toll on the body, and can be quite physically and spiritually burdensome for those who aren't prepared.
Dark magic is very weak to Divinity and the powers of the Light. It cannot heal, and it is very rare to be able to use them in a way that improves life.
One must be incredibly skilled with natural magic to be able to effectively use dark magic. If the demon you summon to grant you power believes you to be weak, that demon will kill you without hesitation or remorse.
The magic is fueled by dark and painful thoughts and feelings such as rage, sadness, and bloodlust.