Dark Angels Fallen

[Nabterayl]

Hey guys,

Something I've been wondering for a long time: what is the big deal about the Fallen? I haven't read the Heresy novels concerning the Dark Angels (hence why I'm asking this question), but from what I understand it sounds an awful lot like the Dark Angels are terrified that somebody might find out that, once upon a time, some Dark Angels fell to Chaos. Unlike, you know, EVERY OTHER LEGION EVER.

...

Are the Dark Angels really planning to spend an unforeseeable amount of time hunting an unknown number of traitors whose fate, not to mention whereabouts, are unknown, because they can't stand the thought that somebody might find out that such traitors existed once upon a time, and might still exist? Do the Dark Angels even have a reputation of not having any renegades on their rolls?

Or ... is there something else going on? I mean, I can accept (and love) space marines being insufferably self-absorbed pricks, I just want to leverage others' reading.