Demons

Demons are the native denizens native to the Plane of the Abyss. Demons are spawned from the God Tartarus themselves, from the ever-changing energies of chaos and destruction in the infinite depths of the Abyss. They are the living instruments of oblivion, personifications of ferocity, vile perversion, and elemental devastation. They exist solely to destroy and bring all of creation to ruin. As a species they are barely contained by their monstrous forms, demons are creatures of raw physicality and rage, the embodiment of everything malign about chaos.
Demons are constantly attempting to invade the universe and destroy it, the only thing in their way is the Devils of The Nine Hells. The majority of Demons are funnelled out of the Abyss and into the Blood War, a never ending war on the layer of Avernus against the Devils of The Nine Hells. The Hells protect the rest of the Universe from being overwhelmed by the spawn of the Abyss, striking down the infinite waves of Demons since the early years of creation. Because of this Demons despise Devils more than anything else in creation and are enraged if they ever encounter one.
Language: Demons speak their own language of Abyssal, that is almost exclusively spoken by Demon Lords.

Biology:

Demons do not need to eat, drink, sleep and they do not age and can not reproduce. Demons are also genderless and have no concept of Gender.
Unlike mortals, Demons do not possess souls or free will. They have a set and strict identity and are incapable of change. If a Demon dies outside of the Abyss, they return back to the Abyss, reforming almost instantly at full strength, but with no memory of their former life. As long as the Abyss exists Demons can not be permanently killed.

Hierarchy:

All Demons are subservient to the God Tartarus, but there is no official hierarchy present in the Abyss. Due to a Demons innate chaotic nature the only modicum of hierarchy that exists in the Abyss is the one imposed by a more powerful Demon.
The most powerful of all Demons are known as the Abyssal Lords, or the Demon Lords of the Abyss. They hold a position of preeminence among the other denizens of the Abyss and are the only Demons with any semblance of personality or intelligence. 
Due to the infinite nature of the Abyss it is unknown how many Abyssal Lords there are, with only six currently named. Many speculate that the Abyssal Lords embody primal urges or forces of corruption.

Origin/Ancestry

Fiend

Lifespan

Immortal

Geographic Distribution

• The Abyss

Patron Deity:
Tartarus - The Tormented One