Limbo

Limbo, also known as The Cosmos, or The Void, is a dimension outside of the universe. It is beyond the backrooms.

Description
Limbo is an endless black void with small shimmering white specks and large black islands. Limbo is highly dangerous because of its affect on sanity. It is know that prolonged exposure to limbo or a being from it is highly dangerous. Limbo is the birth place of elder gods. It is around 1 trillion miles large and once it is exited it is easy to enter other universes. The closest point in the universe to limbo is the top pole of the backrooms. Limbo has a corrupting quality, it is known to infest beings and locations, sucking them into limbo. Limbo is highly dangerous.

Relations to Sub/Negative Levels
In the backrooms there are levels known as negative and sub-levels, these levels appear strange compared to most of the regular levels, this is because of Limbo's corruption.

Negative Levels
Negative levels appears to be densely paradoxical and go by names like Level -0. The negative levels are actually parts of the backrooms completely corrupted by limbo. The laws of physics have been corrupted and shattered, hence the common paradoxes.

Sub-Levels
These levels are much more confusing. The sub-levels are versions of regular levels from a different timeline, the timeline is merged with this timeline via limbo. For example, level 2.1 is an alternate version of level 2 which has been put into this timeline.