Esrevinmo is the reverse of the Omniverse, with the exception that it is much larger.
While being very similar to the Omniverse in terms of structure, the Esrevisnmo is actually the birthplace of all Omni-Gods and is where entire civilizations of them form. However, cosmic entities that are strong enough to influence even slight percent of the Esrevisnmo are able to erase Omni-Gods like Omni-gods can do to regular humans, so their power balances out.