Once in the good days, I played a lot of Kobold Camp rather than with dwarves. I embarked on the mountains, and headed straight for my destination.
The bottomless pit.
Having already discovered the UG pool, I had a vision of emptying the pit of the creatures, flooding it with the river nearby and then emptying it all, carving around the pit levels to make walkways and rooms and so on.
It worked, armed with a lot of wooden arrows, every critter inside(which were surprisingly few in number) were soon full of more arrows than organs. The kobolds did a little victory dance, moved their stuff inside and began work.
By the time my camp was eligible for moods, I had managed to get the pit filled with water and closed the pathway. Probably dropped a few levels of ground on it, or something, or maybe I had gotten a mechanic migrant by then. That's not important to this thing.
Finally ready to get started on the housing around the pit and so on, my miners got to work after I designated every level. The mood was ecstatic, the camp was all thrilled of the bone toy boat a pup had made in an estranged fashion, and all was good.
Until the point where I noticed a message saying the said kid had fallen into a deep chasm.
It was odd, I checked around but there were no enemies, suddenly angry kobolds or creatures that could have pushed the kid over the edge, literally in this case.
I should have looked around more carefully, but that's that.
I unpaused the game, and kept going. Nearly at the end of the mining, I suddenly got an announcement that a kobold had starved to death. This time I had a corpse to zoom into, which I did.
And I found two other kobolds, in a small ledge which had yet to be mined open to the rest of the camp for some reason. All were upset, starving and dehydrated. That, and wet.
By the time the miners got there, they all died off, one by one.
It was not really my most shining of moments with kobolds, but I at least found out the reason for so many of them to fall victim to mysterious forces.
While my memory is sketchy, I'm pretty sure I also used the flooding-source as a water-source. And my map was one with two biomes nearby, unfortunately, this was where the river was at.
Came Winter, the river froze first in the lower part of the map, gradually working it's way upwards. Now that wasn't bad.
But when Spring came, and the top part thawed out, it was unable to push through the ice, so it pushed out straight into my camp.
I had yearly floods that by the end of the camp had claimed those three kobolds to starvation, and a dozen had walked by at the wrong time and were swept in the pit.
Then the goblin ambush party showed up at the top of the pit, and sniped enough kobolds dead to start the tantrum's.
It was sort of hilarious.