One of the very first tests of Dwarf Fortress modding I tried, was playing around with the Ethics parameters for civilization entities. Naturally I wanted to see if it would be possible to tinker up a civilization that would be able to kill (and then butcher, use the materials, etc.) of other sentient races. A big success.
For purposes of testing these proto evil dwarves embarked with some Elven slaves. Said slaves were then commanded to be butchered successfully. Soon I will have to conduct a test to make sure the materials created via this process are actually usable. To be especially horrific, I will need to find a way for one of my dwarves to have an accident of some sort, to see if they can be similarly... reclaimed.
Good times. The df wiki has been especially helpful here of course. Interestingly enough one of the examples on the wiki is for a Dark Dwarf civ+race. Good to know I am not the only one with this great idea. Most of the mods I have seen from the community have been focused on other non-dwarf races; Illithid, Drow and the like for the most part.
I must say though, that I may get inspired to create an Evil World mod here; filled with all kinds of nasty fun creatures. I had originally thought of a Warhammer Fantasy mod, but someone else is already working on one. One of my fun ideas for such a mod was to actually write up some unique megabeasts to represent the 4 Chaos Gods themselves. Pity thus the poor fortress that has Khorne wander on in.
Being such a Warhammer fan, may still work on some of these ideas anyway. No wish to compete with another mod project but I can always use them myself or share them with a few friends. Warhammer-themed DF mods may work well to hook a few more folk on this game.