Yog-Sothoth is an omniscient overdeity that is locked outside the multiverse. This being is said by its worshippers to be coterminous all of time and space. The Necronomicron describes it as the "The Key and the Gate" and claims that it is older then Eru. It is often depicated in illustrations as a mass of glowing spheres.
Although Yog-Sothoth cannot enter the multiverse, it is able to influence it through avatars. Some of these avatars are benevolent and will offer great knowledge to those they consider worthy. Others are more hostile and will bring great harm to those who anger them.
On occasion, Yog-Sothoth will mate with beings throughout the multiverse and produce offspring. Some these beings have become Outer Gods, powerful cosmic beings that have the ability to destory entire universes. These entities include Nyatharlotep, Shub-Niggurath, and Ouranos. Both the Elder Council and the Archdevils view them as dangerous enemies who are a threat to existence. It appears that Yog-Sothoth does not care in the slightest in what they do to its own children.
- Omniscience Yog-Sothoth is aware of everything that has happened, is happening, and will happen in the mutliverse.
- Source Manipulation Yog-Sothoth, being a Great Old One, has the power to manipulate raw Source energy to his will.
- Knowledge Projection Yog-Sothoth can give any being any amount of knowledge, although it may cause that being to become insane.
- Absolute Immortality Yog-Sothoth's existence is linked to the multiverse so that as long as it exists, he also exists.
- Avatar Creation Yog-Sothoth interacts with the world using avatars which vary in personality.
- Reality Warping Yog-Sothoth possesses the ability to alter the reality, although he rarely uses this ability.
Yog-Sothoth cannot physically enter the multiverse and is forced to reside in the Void.