Then it would be "nazis'" for the plural posessive form. *inno*

Yeah, I'm not even going to try to parse that one, it's just completely bizarre. I think the main problem is that your modifiers are all over the place. Do the asses in question belong to the nazis, or to you? So, we are the "grammar nazis", and our asses belong to you (Asarnil). That'd be "All your grammar nazi asses belong to me" or more precisely "The asses of all you grammer nazis belong to me". I don't think there's any way you can work it such that nazi takes the possessive form like that, unless you're talking about multiple asses owned by one or more grammar nazis (perhaps in the sense of an ass being livestock). To wit, "All the grammar nazi's asses belong to me", which is a bit contradictory. Or "All the grammar nazis' asses belong to me", which implies that multiple grammar nazis with multiple asses are being spoken of. If you mean that you, in the future will take possession of the asses, you might say "All the grammar nazis' asses will soon be mine!"

Thanks for playing. *Switches mindset out of pedantic*