Hmm... Those are some good questions. I actually thought about that before, but never really cam to a conclusion. I would presume that technically, whoever controls the Omniverse is the only one who is truly Omnipotent. They would probably get downgraded to Nigh-Omnipotent.
^ Problem with that theroem would be that the Omniverse includes every single Verse. (This includes ours, and even marvels.)
And its quite obvious marvels verse has a omnipotent being. So there must obviously be some sort of conditioning as within that verse they are omnipotent, but what would they be in the omniverse? Quite the hard question.
The mere multiplicity of Omnipotent effectively downgrades them to Nigh Omnipotent by default (each limited by the existence of others). As to who would win or what would happen, we ultimately fall back to the meta-fictional side of the subject. In other words : whoever writes the story unilateraly decides what happens and what doesn't, and each writer is the ultimate reference when it comes to their own characters and setting (makes sense, it's their own creations and turf after all). Each reader is free to reason about what would be more probable according to various factors, but "truth" is the writer's call.
The only problem I see with this DYBAD (By the way its a Honor to see you reply to my question :p) Would be that within the omniverse every single verse exists. Marvel, DC, And ever personal created stories. And we've seen those companies created 'True' Give or take omnipotent beings. So how would that work on them loosing their omnipotence?
What I believe is that any being that can exit into the Omniverse, is omnipotent, and every verse within the verse is omnipotent in some way as well, in which only its maker can enter it, not other beings. But this contradicts the ideal that omnipotence is only one being, and that they are limited to not being able to do something thus making them not omnipotent. Very much a headache.
True, reconciling absolute definitions and relative facts is a major intellectual challenge ^ ^; All things considered, I'd say there is ultimately no Omniverse-level Omnipotent, since not only are there many Omnipotents in many fictional continuities, but each of them is only Omnipotent on its own turf (writer's insurance), while true/hardcore Omnipotence is supposed to be absolutely unlimited and unconditional no matter what. So they simply are a dominant caste of Nigh Omnipotents, and whoever stands in its own domain is victorious in a versus scenario. That's all the sense as I can make of it anyway ^ ^
And I thought the same thing, If anything I believe that it would be 1 of the 3 scenarios.
A. Everyone is omnipotent, thus leading to possibly a soceity of omnipotent beings.
B. The Verses they created is omnipotent, (Meaning the verse itself is the author) and can not be affected by these beings called "omnipotent" as they loose it upon entering the omniverse
C. Everything in the omniverse would be lowered to Nigh-Omnipotent (including verses) so they can not be destroyed by other 'nigh-omnipotent' being same with the beings themselves, and these beings only turn omnipotent while in their verse.
However for C I believe that it could differ in the way that, A. there is no omnipotent being point blank or B. There is however one true omnipotent being and that would be the god-god, The person who created everything (What we humans believe to be god or etc.)
I like to think of it as that even if they leave a verse they still have the power to rule it from outside, omnipotence is basically the ultimate justification power, it can literally do what it wants without question