Quote Originally Posted by Jmaximum View Post
if II is 'the lost' and XI is 'the damned': maybe Russ took out II and XI become the Legion of the Damned? A legion whose genetic mutation actually turned them into spectral undead marines maybe?
My impression was that the II is "the lost" and "the forgotten" and it sounds like the entire legion vanished in a suitably mysterious way (not uncommon in the 40k universe). The XI was "the purged" and was wiped out by the wolves for genetic flaws or something similar. I don't really have a whole lot of evidence but that's what I've assumed from everything I've heard about them.