Swordbaldness:
First embarkation. 210+ dwarves have made a pretty home and are getting bored with fending off goblins and pleasing the dumbnut of a Countess (Black bronze? What, I can dye some bronze black, ya jerk). I decide it's time to enable Justice, as I have the cells and Captain's Rooms ready. Boy was that stupid. After years of ignoring the Countess, I had accrued a fair number of beatings. Immediately, 6 dwarves are dead. Surprised? No.
I let the tantrum spiral continue, because it's the most interesting thing they've had to do for some time. Now, I guess because I had two meeting places/statue gardens, my fortress was rolling in children (well over half the population). Not only does the familial relationship situation feed the fire, but ... you can imagine bloodthirsty children roaming the halls, utterly destroying pantywaist nobles and elven dignitaries. Many of you have experienced it.
The last dwarves remaining are a group of champions (that refuse to tantrum because they love bloodshed!) and a dozen or so children. It's Lord of the Flies, man. I lock the champions in a closet so they can starve and wait for one of the kids to go berserk. And one does...
The best bit, the surprise, is that she calmly waits in a corner of the dining room. It's situated at the crossroads of all pathways in the fortress, and has the best direct access to the food and booze. She's just lying in wait there, brutally murdering everyone that comes by. When someone even gets close to the doors, she smells their flesh, springs out, rips them apart with her hands, then runs back and remains dead still. The fortress ends with a dwarven caravan arriving just as the last helpless child is slaughtered. The merchants, a melancholy human diplomat (this isn't a nice place by now), and the murderous preteen are left.
Second embarkation. Reclaim with a couple dozen ass kickers. I relieve them all because I'm stupid and need haulers to clean up the mess left behind. After a while, a dwarf goes down into the mines to haul some junk. Down there he finds a little dwarf girl, seemingly left behind in the chaos, sullenly brooding, calmly awaiting the chance to taste more blood.
Tantrum spiral part two...