The Omniverse is a collection of multiple Megaverse on other side. It's everything that exists, doesn't exist, anything in between, below, above, anything any being within All can imagine with a name,except God.
Those without an actual name technically exist outside the omniverse. This, and The Outside is all that is outside of the omniverse, in The noname verse All else is The Box, which contains all the omniverses, no questions about it....maybe. But Aarex thinks there is nothing beyond our omniverse.