The backrooms

The backrooms is an infinite dimension on a whole different plane. The rooms resemble a typical office building with yellow wallpapers, moist carpets and dim lighting. however, the rooms here are not normal, instead they are an imitation of already existing rooms, they get created from wanderers and researchers memories. Almost like explaining how a dog looks like to someone who's never seen one, and then asking them to draw it.

null zones are the only way to acces the complex. They may appear anywhere, at any time and of any shapes and sizer. They may appear somewhere in the middle of ocean while being just a 0.6cm² wide, or could appear in a crowded place like a mall, a concert or a school and be very big, nothing can predict the next null zone location as of now. Async is involved with the null zones appearing, possibly with them opening a portal and causing a massive earthquake, after which the missing person count started growing rapidly.

not much is known about the green glow as of right now. But theories suggest that it might be responsible for creating new rooms, hallways, etc. Its also speculated that it produces gamma rays.

the life form is a mutated (possibly a still life) version of Hay Bacillus, it needs to kill people to survive and reproduce. If the bacteria finds a corpse, then it will take it over and produce the life form, which is a tall, skinny creature thats only purpose is to chase and hunt down anyone it could find.

furniture crabs are just alive furniture, it may move around from time to time

Still lifes are an imitation of life by the backrooms, it being created from wanderers and researchers memories and other stuff. It also may copy the person itself and copy the originals behaviour, for example, if a person gets in the backrooms and acts aggressive, arrogant, etc. then the still life will also be aggressive. The same thing goes with memories. it also can copy things from reality, but it will be less accurate.

Async is a company that found out about the backrooms, it was firstly introduced as a solution to problems, such as housing problems, storage problems and etc. however, the idea was scrapped after a motion detecting camera found an unknown lifeform.