Okay, I really don't know what just happened. Here is the story of my butcher-dwarfs of Rareabbeys:
I recently hit the 100-dwarf mark, which is a first for me, and because my outside is so well-defended I've been getting a little bored with this fort. With a Goblinite-armed military of thirty strong (or weak, because they take so f**king long to train now,) So I decided to try my luck at colonizing the demonic fortress located in the third cavern on my map. Using DFreveal revealed page upon page of rotting and skeletal undead of almost every cavernous race imaginable. Snakemen, amphibian men, ant men, etc... for no less than ten pages when I first checked. But I had seen miasma constantly and the rotten carcasses of the ant people in the fort, so I assumed that the zombies were just rotting and dying over time. Also, I had read stories of un-trained dwarves easily punching the heads off of the rotting zombies' necks in the past, so I was fully confident my army, trained on captured prisoners, would be able to handle them. My biggest worry was that the miasma would give my dwarven soldiers some unhappy thoughts, but keep in mind that these are all happy, happy dwarves; Rareabbeys is the bees-knees, the place to be for dwarf, elephant, and war-hound alike! There was no way they would ever do something like revolt in the middle of a siege on their slade-clad target. I prepared my fortress for battle by placing two [2] successive weapon traps, each fully loaded with giant iron axe blades, in a one-wide corridor....
This is where things became...strange...
Being the idiot commander that I am [queue facepalm moment,] I had neglected to order all of my civilians inside the fortress (my burrow, that is, which is as large as the expanse of my entire fortress,) but I had not expected it would be such an important order to give. Because of this lack of specification, for whatever reason, although presumably to dress the rotting flesh of the zombies, my chief medical dwarf decides to trek into the fortress. Alone. With no animals. [I had caged all of my war animals, as they were causing a slowed frame rate and were unnecessary at the time.]
I snap into action. Although it had caught me by surprise, I viewed this as an excuse to finally put my military to good use. They charge the fortress through narrow corridors, in a hope to save their chief doctor, of which the survival of was an absolute necessity to the function of the fortress. This was now not a siege for the glory of Armok, but a high-priority rescue mission.
They arrive at the fortress, with the commander and captains at the fore-front of the army, and the whole force charges in, slaughtering the first floor of snake and amphibian men with unparalleled ease. They choke and gag on the miasma, but the doctor is located and flees back to the fortress with no more than a few bites and handful of bruises. More zombies erupt from beneath the floors. There is no turning back now...
Axes are swung and daggers lashed but the dwaves prevail to the second floor, a small, one-wide labyrinth of undead. The commander and captains go on, but this is when I notice something strange: multiple dwarven soldiers are carrying barrels of dwarven ale into the labyrinth. "...Why?" I thought. "Well... perhaps they expect a long siege, and so they thought ahead for the fortnights they shall spend in here. Good initiative, dwarves!" But then I noticed some other things:
First: A random blacksmith had made his way into the labyrinth and died. A shame.
Second: Only the commander and captains had advanced to the second part of the labyrinth. The others were not following.
Third: The ground around the other soldiers is spattered with dwarf blood.
Fourth: The dwarves are all killing each other.
...What? They're not unhappy dwarves, not even the injured lot! No dwarves are throwing tantrums...why are they killing each other!? Slowly my military is crumbling to the savagery of its own components, and my commander and captains will fall to the next floor of the undead...
I believe it has something to do with my mass-designating the entire labyrinth as kill orders, but of this I am unsure. Perhaps the narrowness of the corridors caused one dwarf to collide in combat with another? Or perhaps the miasma obscured their vision until one dwarf attacked another, causing the victim to erupt into rage? Perhaps the evil spirits of the demonic fortress incited the dwarves to brutality? The mystery prevails. Thus ends the story of the butcher dwarves of Rareabbeys
[Seriously, idk what the f**k happened, but they were all killing each other and killing snakes and there were dwarf parts all over the floor oh god. I had to force-close the program once a goblin siege showed up on top. I probably could've handled them with my traps, but I had lost so much it was game-killingly bad. Can someone tell me what I did wrong?]