So I abandon a fortress and go back to look at the battles in Legends to relive some good times when I decide to see what the orcs were up to before my sacking my fort. Mostly normal stuff - border skirmishes with humans, 3:1 in the orcs' favor, but usually with about equivalent casualties on the battlefield (humans don't send half their soldiers in the nude). Anyways, a few battles back, I come across something truly epic - Thima Baci, the Siege of Whipping.
653 elves versus 34 orcs, with the elves taking the offensive against a three tower dark fortress in the year of Armok, 299.
End result: 235 dead elves, 0 dead orcs, and seven seconds of holding "page down" to scroll through 34 orcs devouring 235 elves (I take it they were just eating the choice parts).
And that's not all! There's 260 years of fighting between the elves and orcs with orcs feasting and elves fleeing into the Forests of Splattering! Each year, the elves brought more and more troops fighting border skirmishes and attacking the same damn dark fortress (which they never took), taking about equivalent casualties (4 or 5) up until 255 when suddenly they lost 172 out of 435 and kept at it for nearly every year thenceforth, with similarly demoralizing names (the Clash of Routing, the Roasted Onslaughts...).
Final tally: 4255 dead elves, 0 gain.