It feels wrong the Trespassers haven't killed us all when they can apparently devour realities without us being able to do shit.
Actually, to revisit this discussion since I've only actually bothered reading the IC's opening post just now, it doesn't strictly say that all the universes
themselves are at risk, only the multiverse. Which is sort of like how a debt crisis could hypothetically break the European Union but it almost definitely won't break all the constituent countries as well. And not to mention that one of the reasons why those reality-breaking things have gotten released is because the denizens of a bunch of settings have become able to break reality pretty well themselves.
Because it could very well be that the multiverse is going to end not because a bunch of rampaging eldritch locusts ate everything, but rather because the universes that were powerful enough to stop them decided "fuck it" and just used their own power to break free. In which case I guess this game might turn into a more RP-heavy political/diplomacy game about trying to convince the more powerful settings to actually commit military resources to the war for the sake of a bunch of people they don't know, rather than just sitting there in their own little worlds, cutting down anything that wanders onto their lawns like sociopathic parodies of the stereotypical elderly.
Alternatively, there might be infighting. I mean, they're all competing for the same food resource after all, so it wouldn't be too surprising that some would be hostile to the other. Hell, some of them might even assist, because if the multiverse continually grows unless it is completely consumed, then it'd be in their long term interest to allow it to continue surviving so that they can continue eating. It isn't like they even need to kill people instead of say, just shoving them into another universe and letting the denizens deal with the ensuing refugee crisis, seeing as they eat the fabric of reality as opposed to people.
Alternatively alternatively, they might have their own agenda that isn't actually just about devouring everything. Maybe they originally had to escape their own universe for some reason but then kept on expanding out of paranoia because of the event that forced them to flee in the first place? Maybe we're just fighting stragglers, deserters and renegades while the rest go do their own thing in the regions of nonexistence that they have devoured/captured? Maybe when we finally encounter the more powerful ones, they're just randomly kill each other, break the universe with some sort of catastrophe and as they leave, we'll catch a glimpse of an insignia with text reading "ARM"?