Rather doubtful...the Eldar hate the Necrons even more than they hate Chaos, if that were possible. The Eldar and Necrons were fighting each other long before the Chaos gods came into being--in fact, the Chaos gods were the product of all the turbulent emotions felt by the Eldar, the Krork (early orks), and all the other species that the Old Ones created or used to fight the Necrons.

If the Necrons seem to ally themselves with another army, it's usually because the Necrons either don't notice the other army or don't care that it's there. In both these cases, the Necrons tend to have some other goal that is more important than just killing anything that moves. This might be neutralizing a more dangerous or immediate threat, securing a position/tomb complex/artifact/etc, or carrying out an order given by a C'Tan. However, I think that even the Deceiver would give much more immediate target priority to an Eldar force than he would to humans or Tau.

You could always screw the fluff for gameplay's sake...sometimes you really can't justify something in a game with established fluff, so you just ignore it Happens to me all the time with my friend's Necrons.

 

Thanks for the help! It looks like i'll just screw fluff for this one.


Edit: actually another question, would the deceiver have any real reason to infiltrate a eldar craftworld? Cause I think that might be also an interesting idea for a backstory for eldar. It might be a bad idea, but it sounds different than to other fluff stuff I've read.

 

There would be a good chance that he would infiltrate, or try to infiltrate, a craftworld just for the sake of infiltrating a craftworld. He rather likes doing those things after all.

To give a more understandable answer, if he could find a way to infiltrate a craftworld, he would. You could use an idea like, "He ambushed some rangers, toke one of thier places a stumbled back to the craftworld complaing of an ambush."

 

There is a mention of this sort of manipulation in the 'cron codex...something about a weapon that could actualy destroy C'tan being removed beyond the eldars reach. Abbadons Planet Killer ship as far as I can tell. So yeah, Id say he could, would, all most likely has.

 

The planet killers were used in one of the black crusades, I believe that they, when used together, were supposed to kill the C'tan, though all they really did was put the Void Dragon to sleep.

 

The Planet Killer I believe was Abaddon's flagship, the ancient Eldar weapon he acquired from the gothic sector (I think) was a Blackstone Fortress which the Eldar called the Talismans of Vaul.

They posessed a powerful Warp Cannon that is enough of a threat that the Deciever has been going out of his way to destroy them, they were designed by a Smith God for the express purpose of killing the C'tan. Whether they were up to the task or if they still are now is I think unproven/undocumented. Though since out of the last 6, 4 have been destroyed and 2 are in the hands of Chaos, we may never know.

 

Dead on Emerald Cat.