One time on one of my ultra-low population world experiments the northwest corner of the map was left alone so long... that uh... I don't even know how to explain this:
About half of the shrines were full of little deathmatch battles between all sorts of titans. I ended up dragging around the pieces I was able to reanimate, though I never got my hands on an intact firebreather (just a head) or web shooter (just the body >.<), but I don't think they keep doing that stuff when reanimated anyways, since they just zerg rushed anything in sight.
That world was mostly cleared out, so I tried out a couple more and got one that offered me fortress mode, goblin adventurers from either one of the two intact gob civs, or the usual human outsider.
Not sure why, but I really enjoy playing as a gob, you get the not needing to worry about eating/drinking benefits from being a necro (or only needing blood as a vamp) without the uber stats/temptation to form a horde of shambling abominations.
I tend to get bored just keeping up with the needs of a new adventurer and either go looking for
that which men should not possess or start playing with dfhack or the raws.
This guy though, the only thing I did with dfhack was making a set of artifact steel and a platinum mace with a quicky reclaim group of dorfs donating their forced moods after some brainwashing, the rest was all done with his own green hands.
That's him getting ready to chip away at another hydra, the first one I cheezed to death by standing up on top to the south of the lair entrance, forcing her to swing at me from an awkward angle while I dodged side to side doing quick bash+manual moving so she couldn't commit to a solid "wrestle+murderspam" set like she did the couple of times I had to go back to an earlier save (shortly after I had picked up the armor/mace actually >.<, yes I savescummed there because I had a grudge at that point) and just kept at it.
I started before Samurai Jack came on, and I finished after it was over, so close to an hour of bashing her about the heads and lungs and so forth, went from something like 400/1100 to 400/1600 I think? Currently:
Oh yeah, the fort I used for the artifact gear?
It was destroyed by a forgotten beast.
That same beast is depicted on the mace.
The depiction on the mace is of it killing a dorf 192 years ago.
That dorf was killed shortly before the fort fell, in fact.
That beast, after a long circle-strafing battle, was the first kill with that mace.
Awesome.