@CaldizarWe designed MR's universe system to be able to incorporate godlike entities that are part of fandoms, by tying their powers to their universes (or multiverses inside of Existence). Outside of those dimensions, they do not have that level of power. If we say they can—well, your character may not want to get involved with the rest of Existence's battles, but we cannot say, realistically, that there are
no Living Gods who will share that indifference. If any universe's godlike beings could exert that godlike power over Existence, it would long since be destroyed or enslaved.
Based on this reasoning, it would be best to keep his godlike powers in-universe. Even though he's part of a fandom where his powers are godlike in an entire
Verse, that "Verse" should again be in its own layer underneath the umbrella of Existence.
(But! I would not go so far as to say that this should eliminate his powers outside of his dimension. If I were trying to figure out the power, I'd see it more as a
supreme control of self but not necessarily the things around him. This might mean invulnerability of a certain kind (which one of my characters has!), but it wouldn't mean the ability to control someone else's person at will, or to create an attack of perfectly irresistible power, both of which would lead to the balance issue I mentioned earlier.)