The dangerous entities of the Backrooms did not always exist. Many thousands of years ago, the Backrooms existed only for the preservation of humans. Then the entities came, and started tormenting and driving humans from their native lands.
Finally, humans are nearly extinct in all the backrooms. Only one level known as the Frontrooms remains free of Backrooms entities. Any beings that want to preserve humanity seek to keep entities from establishing themselves in the Frontrooms.