I'm not sure why none of MY brethren have chimed in yet, but the True Kin and the Tau have a long history of working together. Remember when we helped you fight the Tyranid off the planet of Vigos? We sent our--err, soldiers--to the front lines and saved so many of your lives. And all we asked for in return was an exchange of culture. We love getting to know the younger races. And as we've proven countless times that family is the most important thing to us, I don't believe anyone could doubt that we will fight and bleed and die for our Craftworld cousins. Craftworld Iyanden knows firsthand just how far we will go to protect the Eldar race. If the True Kin know anything, it's that anyone or anything that helps keep members of the great Eldar race (even our misguided Craftworld cousins) alive is worth investing in. I for one welcome the great faction of The Young and the Old.
the imperium are a doomed the eldar will destroy you and the xenos you hate will destroy your false god the emperor
I'm not sure, the Tau are a relatively minor player in an area of space where I am not aware of any particular Eldar interest. In absolute numbers, I expect Eldar to help the Imperium a lot more times than they would help the Tau.
