Hey, I just had my first visit from the Circus and (after I stopped cursing) I began to wonder: would it be possible to simply flood the Circus? I mean, a nice chunk of the Clowns I saw were made of fire, so could I just ready an aquifer, open up the Cotton Candy, and wall everything off until the Clowns drown?
To be specific, there's three essential problems here...
1: Fire is not fire. They are made of 'fire' but it's really just a solid material that has a very high temperature - if that much. You'll also see creatures made of water and vomit that behave like perfectly reasonable solid creatures. If anything, think of it more as Balrog "superheated stone chunks" than actual wisps of flame.
2: Clowns do not breath, specificially [NO_BREAHTE] means they cannot be drowned or strangled. Well, they can be strangled, just doesn't do anything!
3: The circus has extremely large, open pits to the void. These are bottomless holes into the unknown through which water simply vanishes. Attempting to flood the circus would, at best, result in a very spectacular waterfall. At worst you would flood your own fortress because you forgot how water pressure works.
The pits are actually a very curious thing when you think about it. The lowest available spot on the map is hell itself, but the pits go down infinitely from there. And they do go down infinitely. The world is not round - civilizations on either edge of the map do not take the short route crossing the map's edge. The world is like a slice of cake, except it goes down infinitely (which would be incredible if cake were infinite).
The demons do not come from the pits. They come from other parts of the underworld, wandering the depths aimlessly in their prison of semi-molten rock. In fact the demons can fall into the pits, and be devoured.
The common consensus of lore is that the demons of ages past owned the ball of slade. The gods covet this 'planet' they own, and cover them in a sky of rock, building their world atop it. The anger of the demons and the flames of their bodies keep this material semi-molten, made divine and incapable of truly melting, it exists in a limbo state, burned by the pits of hell but hardened by divine protection. Yet as the world grew, fissures appear, allowing certain demons to escape, taking leadership over human and goblin civilizations in particular, their bloodlines diluting into common night creatures, before the gods seal the cracks with adamantine spires. The only remaining openings, the underground structures, are sealed by brave heroes using adamantine blades to form a barrier, keeping the structures sealed. The power of this draws common animals and citizens to keep the sword in place, even after death they remain, zombies existing solely to keep intruders at bay and keep the seal safe - until some dumbfuck dwarf deconstructs it.
All this ultimately begs the question... what exists below the demons? What are the pits? What could there be so deep, so buried, so ancients, that the denizens of hell itself refuse to descend any lower? If the gods built their world by encasing demons in the durable semi-molten rock, then what did the demons encase in their impenetrable slade? What truly old and powerful force of the universe itself dwells within a prison of slade, an indestructible barrier that, with time, has slowly started to fissure and separate...
We've debated how players become more adapt, dwarven science progressing weaponization to incredible heights that hell itself becomes a mere testing zone for theories. Toady still has something laying in wait. That Which Dwells Beneath must surely be something untame and unmanagable.