@Wyrmwood: That is indeed a logical theory! Whatever Ahriman's after, I think everyone can agree that it's with the ultimate goal of restoring the Thousand Sons to their previous glory (although whether he still intends the "in the eyes of the Emperor" bit is debateable. ). It's just the method that he's going to use that's up in the air, hehe. Personally I'm not a fan of the idea that Ahriman's after godhood for himself. Though I admit that's more based on gut feeling and the impressions I've gotten from what I've read so far, rather than any solid evidence or facts.

For example, this passage from the epilogue of A Thousand Sons:

"(Magnus) let his ambition and hubris blind him to his flaws and the knowledge that there is always someone stronger and more powerful out there. I will not make that mistake. But we are still creatures of flesh and inclined to repeat our past mistakes, so I have been careful to surround myself with naysmiths to rein in my arrogance."

To me, that makes me think that Ahriman isn't after power for himself specifically. He doesn't want to make the same mistakes Magnus did, he doesn't want to start thinking that he's the strongest or most powerful, he doesn't want to let his arrogance overcome him. He's actively keeping people around him that will question his decisions and go "hey, wtf are you doing". Heck, that happened in Atlas Infernal. XD That doesn't strike me as something that someone wanting godhood - and the inherent implication that they'd then become the strongest/most powerful/etc. - would do.

Granted, that intention may have changed over the past ten thousand years... but then again, it may not have.

@SomeRandomEvilGuy: I remember seeing that mentioned. Though I don't know if that really counts as a direct attack against the Imperium - I agree it was most likely to discourage pursuit, but it could've been meant for anyone pursuing, not just Imperial forces specifically. Heck, taking Atlas Infernal into account - if the attack happened after AI, Ahriman could've left that trap for Czevak and his crew. XD Of course, if it happened before AI, then that's moot - but there's always other forces that Ahriman could be guarding against. Other Chaos forces, eldar, whatever.