Join Date: Aug 2009
Location: Portland, Oregon
1. On one hand, I want to say that the AL could easily infiltrate Prospero. The Thousand Sons seemed, to me, a very human Legion. The AL could have probably slipped in some infiltrators by posing them as scholars, remembrancers, or even refugees from another planet.
On the other hand, I want to say the Thousand Sons are very good (an understatement, I know) with their psychic powers. Finding an infiltrator could be very easy if you could mentally scan everyone entering and leaving your planet.
On the third hand (my mom says I'm beautiful), you could say the Alpha Legion also have some very talented psykers in their force. Both post-human and human. I'm sure they could rig up some sort of psychic mask, much like the one we see throughout the Eisenhorn trilogy.
The Thousand Sons are an arrogant lot, for the most part. If they couldn't find an infiltrator off-handily with their psychic powers, I'd assume they wouldn't dig all that much deeper. Not without one of the higher ups to whip them into diligence.
One way or another, I'd guess the AL would infiltrate the very ranks of the Thousand Sons. Rather than piecemeal infiltration like we saw in Deliverance Lost, maybe the replacement of whole units? That would make it much easier to keep the infiltrators away from the real Thousand Sons. So long as their commanding officer gives a valid reason to keep his men away from the actual Thousand Sons, the chance of discovery drops considerably.
From there...well, stuff. Anything is possible. Maybe the planting of life-eater virus in strategic locations. Or vortex missiles. Or a myriad of interesting ways to destroy a planet or society.
Eventually, one way or another, the AL would find a way in, I think.
If all else failed, I'm sure they had a bunch of blanks stored away somewhere. I think they were prepared to fight everyone and anyone. I could imagine they'd have contingencies to fight against a force of very powerful psykers.
2. That's just a clusterfuck and stuff. The AL fluff in modern times is everywhere. I wouldn't even know where to begin.