Board Thread:Warhammer 40k General Discussion/@comment-2253300-20130211000751/@comment-3580035-20130211062747

I'm not actually sure if they describe the Emperor as having 'sacrificed' himself for humanity, which could imply to the average citizen that maybe he simply got too old or something like that to end up in his current state.

With the Primarchs,  I think that just say they individually went off to fight unspeakable foes and simply disappeared, and will return one day.