Abyss

The Infinite Layers of the Abyss, home to the chaotic evil demons.
Tanari: Demons born from humanoid souls. They undergo multiple stages of development, starting as larvae and progressing to different forms.
Obyriths: Ancient beings from a different multiverse. They have repulsive and amorphous shapes, each being unique.
Shard of Pure Evil: Created by the Obyriths, this shard contains the essence of billions of their own race. It has the power to tear open portals to other multiverses and unmake realities.
Tharizdun (Elder Elemental Evil): A powerful entity who sought to corrupt the astral plane using the Shard of Pure Evil, enabling the Obyriths to invade. Imprisoned by the gods.
Obox-ob: A demon who collected the Shard of Pure Evil but was overthrown by other demons in the attempt to plant it in the astral sea. The resulting vortex created the Grand Abyss.
Grand Abyss: A massive fissure into reality caused by the vortex created when Obox-ob attempted to plant the Shard of Pure Evil. Primordials and Obyriths sought to claim the shard within, but their powers weakened as they ventured deeper.
Asmodeus: Possesses a shard from the Shard of Pure Evil, known as the Ruby Rod. This artifact grants him control over all other devils.
Pazunia: The first layer of the Abyss, where most demons reside. It is considered too dangerous to live in deeper layers. Known as the Plain of Infinite Portals/Pools.
Queen of Chaos: Discovered that mortals who die and end up in the Abyss become Tanari. She used millions of Tanari to conquer the Abyss layer by layer.
Miska the Wolf Spider: Absorbed the essence and title of the Prince of Demons. Imprisoned by the Rod of Law, which was later thrown into Pandemonium.
Eladrin: Fought against the weakened Obyriths alongside the Tanari. They played a significant role in the downfall of the Obyriths.
Prince of Demons: Demogorgon, the first Tanari ever born, attained this title. He is a powerful and influential figure among the demons.
Rod of Law: Imprisoned Miska the Wolf Spider and scattered and repelled demons when used against them. It ended up in the plane of Pandemonium.
Beings of Law: Decay and weaken while in the Abyss due to its chaotic nature.
Dawn War: A conflict between primordials and gods, during which the Obyriths and Tharizdun fought for control over the Shard of Pure Evil.