... I think I pissed off the elves.
......what the hell did you do? ah well genocide time for you
I modded the entity raws for the elves so they would send diplomats. When my fortress was large enough to have a Baron, the elves sent a diplomat who lectured my dwarves on the evils of tree-cutting and demanded I stop cutting so many trees. I agreed to their demands, then as soon as the meeting was over designated the entire map for tree-cutting. The next year, the diplomat showed up again. Not wanting to waste my Baron's valuable time (he's one of my best miners), I had my military kill the elven diplomat. The same thing happened the next year, and the year after that. Then the elves ran out of patience and/or diplomats and sent ambushes instead.
There were a lot more than what's shown there, the ambush groups kept spawning for the entire spring. There were about thirty ambush groups in all, many of them riding horses, moose, or war grizzly bears. I was hoping they'd bring unicorns so I could set up a wild unicorn ranch, but the elves in this world don't seem to have access to them.
The really hilarious bit is that they all spawned in the same place, right on top of a retracting drawbridge over the drop pit the Baron had been digging out. One lever pull and several hundred elves and animals fell into the pit. Many of them died, some survived with horrible injuries. I now have a pit full of badly injured elves, war animals, corpses and body parts. Sadly, the magma pump stack is still a few years away from completion. Instead I think I'll fill the pit with water, slowly, and see how long it takes them to drown.