"But I'm a god in my world."
"Yeah? I ate my world."
Upon Poly entrance, we ask that people tone down their characters' powers. This has precious little to do with our undying respect of the City's rather fugly buildings never leave Maemi in charge of architecture, kids, and far more with the fact that we really want to avoid canon differences resulting in OOC d0rama. Even if your character was Teh_Shit in their canon, please always try to accommodate the fact that their other-fandom rival in this Battle O' Doom? Might have been the Big Boss in their home world too. Talk things out, don't try to stress the importance of your canon.
Likeliest chance?
The other side doesn't care.
As regards characters who are specifically designed to be pinnacles of power. That's their canon function, poor dears, and robbing them of their abilities would just mean killing them slowly.
We're OK with those* characters' maintaining the full extent of their powers, insofar as players keep in mind that, usually, characters with the ability to DELETE ALL? Also have a no-interference policy. If they don't, they're asked to please develop it now, for Poly purposes. I know this sounds a bit "stupid" : what's the purpose of having an overwhelming power if you can't use it? But it's also a bit stupid to allow every single character with said power running around, killing things. There're only so many flattering takes on the CRUSH, KILL, DESTROY routine.
Any standard declaration of "my canon trumps yours," or "my char > everyone," or "my char has power X and Y and Z and goes undefeated in his/her canon, so that clearly extends here as well"? Is NOT moderator-endorsed, and subject to player discussion and negotiation. We do supervise applications and the game in its overall, but we can't account for every single post, thread and userprofile in every single character journal – so if you encounter these sort of statements, know that while they might be backed by player logistics, they are not promoted by your mods.