A flight of stairs in a room

[Weismart]

In case you've got 90+ strike and strength, then melee would be better. Ranged setup though would go something like that... Method - Stand straight in front of these, protect melee and use eagle eye. They will hopefully melee most of the time, along with your d'hide / arma will tank nearly all of their magical strikes. The only damage you will take largely is that their ranged attacks.

I think, to begin with, you need to build a throne room, and build a floor in the center of it and construct an oubliette room under it. After that, there are two other methods of getting into it: A big cave entrance that you construct in a garden/fancy backyard. A flight of stairs in a room.

After building one of those two you have the choice to construct a room below, and there must just be a single option for it. After you build those area (s), you can build normally in building style, building treasure chambers, dungeon corridors and junctions, or some other area from above which you wish to have down below too.

Furthermore, if you have not already, performing the Love Story quest unlocks a new kind of dungeon room which adds a whole variety of new dungeon guards that you can add down there, like scarabites, black demons, iron dragons etc., and most of these new creatures are less costly than the original trolls, hellhounds and metal dragons etc.. When I missed anything feel free to ask away again.