Rein

In Solar Storms, the Megaverse is an extended hyperstructure of multiverses.

It is hypothesized because it is clear enough that the entities known as mobius patterns, spectres, and ghosts are not actually native to anything even remotely resembling the Multiverse, or each other's. Some postulate that these entities are not just a part of another multiverse, but of an entirely different existence, completely alien to our own, thus the term megaverse.

In such a case, there are at least four megaverses, though there are possibly many more. Regardless, they all fit under the Omniverse umbrella.