Sorry for the tortured English, but I just like the sound of it better than “be there monsters here?” and “there be monsters here?” and “here there be monsters?” are too-subtly questions.
The question is, does our Burning Wheel game need monsters?
I can think of at least two ways to tie orcs in to the setting thematically—neither of which i’ll mention here, because i’m pretty sure my players want to be able to discover some things along with their characters. So maybe they’re all the monsters we need? But they’re not really monsters—they’re still very much “people”. And they risk becoming caricatures, and letting humans off the hook by providing a convenient “other” to fixate on: “It’s unreasonable to refer to us as ‘cruel’. You need to look at an orc to see what ‘cruelty’ really is.”
Would monsters just distract from the rest of the setting, and the themes of consequences, hubris, nationalism, and other very people-centered, moral questions? Or would they be a welcome break, once in a while?
Maybe monsters need to be tied into the themes—the only monsters are the results of magical summoning. Or maybe there are also some “wild” monsters, but they, too, are the side effects of magic. Summoned creatures that broke free rather than returning from whence they came.
Or maybe something more thematically explicit, but less direct: the unexpected after-effect of the A-bomb was cancer and other long-delayed suffering and death. Maybe magic is similar to radiation in that sub-lethal exposure has long-term side effects. So the “monsters” are simply animals that were far enough from ground zero of some massive artillery spell to survive, and the residual magics slowly altered them over time. Or all at once: Magic gone wrong certainly is a perfect explanation for chimeras and griffons and perytons and the like. Even owlbears. :-D Especially if they are unique creatures, rather than whole races.