Board Thread:Warhammer 40k General Discussion/@comment-8881468-20150204091114/@comment-6078851-20150205155636

the eldar do indeed hold grudges, just like humans, but the reason they hold a grudge against humans as a species, besides the arrogance of their believed superiority (which is an arrogance humanity also has), is because the eldar were friendly with humanity when humanity initially became a player in cosmic affairs (when emps was still behind the scenes) and humans were the ones who first stabbed their eldar allies in the back (i can't remember where i read about that but i'm pretty sure it was on this wiki). however the primary goal of the eldar is to thwart chaos and all it's manifistations, which is the main reason why eldar still occasionally ally with humans. eldrad also foresaw the heresy and realised that, since his own species was dying out, the emperor of mankind was the best chance of fighting chaos, so i reckon at least eldrad's craftworld (and eldrad has some clout amogst eldar so he could probably have attained the aid of a couple more craftworlds) would have been willing to help terra against horus if they could get there through the webway.

and yeah, if the imperium could focus it's entire might against the tau they would be toast, very burnt toast, very quickly. although i have to disagree with you los that such would be the case against tyranids - the entirety of tyranids that is, not just the 'few' that are awake: i think the entirety of tyranids against the entirety of the imperium would be the same result as the entire imperium against the tau - the imperium would be toast very (relatively) quickly (the only reason tyranids are being somewhat slowed is because every species is fighting against them, and they don't have any allies :P). i also think that if the entirety of ork-dom were pitched against the whole imperium then the imperium wouldn't stand a chance. with tyranids and orks it always comes down to numbers (and no-species comes even remotely close to their numbers. though, personally, i think even ork numbers pail against tyranid numbers) and if either could bring their full might to bear then no species could stand against them solo. but because orks fight against themselves more than against any other species, and because the bulk of tyranids are still asleep, the rest of the galaxy can entertain the hope of defeating them. but it only takes one uber-massive and brutal ork to possibly unify all orks, and the rest of the tyranids are coming and are waking. what i want to see is the entirety of orks and tyranids slugging it out. now that i'd say would be an unknown outcome, but i'd still put my money on tyranids :)