You've beaten me, Dwarf Fortress
I embarked on a border between a Wilderness and Haunted biomes. I get about 15 minutes of carving out an initial space and stockpiling everything, when a herd of zombie elks arrive and begin killing my dwarves - including my military dwarf. My mason goes down shortly after, and I didn't have doors built yet, so the elks took out my entire fort.
After laughing about this — I've never lost a fort that quickly ever before, especially not in a pretty mild territory — I put together a second squad of 3 military dwarves and 4 peons and attempt to reclaim. A few minutes into gathering all the scattered items from the last attempt, I get ambushed by zombie elks again. Two of them have names now! My military dwarves manage to take down a few, but the dwarf corpses from last attempt are reanimating now and my second squad gets overwhelmed.
Now I'm just kinda shocked, and determined to succeed. I put together a purely military squad — 7 dwarves with only military skills, 7 full outfits of copper gear — and try reclaiming a second time. Not two minutes into reclaiming, I'm ambushed by three zombie elks and five reanimated dwarves. More corpses are joining the battle as it goes on. I managed to take out eight reanimated corpses before I lost two military dwarves (who then reanimated) and the rest of my squad was overwhelmed by an ever-increasing deluge of zombies.
I had to give up on that location. I could cheat and edit the raws until I get established, but I think it's more satisfying to admit that, yes, you've beaten me, Dwarf Fortress.