That's totally untrue. You prolly think about high elves and dark elves. In WH40k it's a bit different. All Eldars (CW, Dark, Exodites and Harlequins) perceive themselves as a family. Family you may not necessarily like (delicately speaking ) but when shit's on you are able to coop. You really can't compare it to imperials and chaos.
No big surprises here for me, i better watch the backs of my fellow eldar crew and you better not come after them, Alenia is already married. Dude like your work, neat on shadows. BTW i also collect dark eldar and eldar... and a few sisters of battle, but they'd never leave me.
My fury at seeing even a single Eldar reduced to such a state is--very slightly--abated by my begrudging respect for the exceptional skill of your drawing. Well done, Dark Kindred...and stand warned. The Eldar do not forget, nor do they forgive.