I first came across this elf on a small-sized world generated with default parameters. The other elven civilization had been wiped out in around the year 50, as for this civilization, a series of wars of the whole "eating the corpses of dead enemies" thing has been waging since about 10, against three human civilizations. In 44 there was a battle against humans that reduced the elven army from 5 to 1 (they'd had a series of pyrrhic victories leading up to this). This one elf (the one pictured) had held out on her own until the end of worldgen, when I got a quest to kill her. The quest giver told me she'd killed 201 humans and then reeled off a massive list of his relatives she'd killed:
After arriving at the last forest retreat in the world, and killing 10 civilian elves, she caught site of me and announced herself. This took around 10 minutes as she reeled off her kills (one of the best DF experiences I've had, the huge variety of lurid descriptions and the lists of dozens of leaders of nearby human groups were staggering:
Needless to say, she thrashed my hammerman, in the time it took for me to take a single step, she's covered the distance from the edge of my vision to me, and in the time it took for me to miss with an attack, she'd knocked me unconscious and pulverized me with her fists (she had no weapons or armour). This happened three more times until I made a crossbowman and went after her (though it still took almost a dozen bolts to kill her, and she damn near killed me in the process).
I then used the same world and history seeds, only I extended the amount of time the world stayed in generation (via the parameters). She ended up finally dying, to an otherwise completely unnotable human (no other kills or past battle experience) in 144 (having been the only elf fighter for the past 100 years) and with the number of kills you can see in the image at the top (she devoured every single one of them afterwards ,I believe. The last forest retreat was destroyed after this battle. As far as I know, the last elf alive is on the other side of the map, being the only prisoner taken from the extermination of the other elven civilization.
Well, I was impressed. I'm about to generated the same world in 143, so I can try and fight against her just before she dies to see just how good she gets. Or, maybe I'll kill the human who ends up killing her, then play a series of fortresses to pass the time while she gets even better...