Board Thread:Warhammer 40k General Discussion/@comment-71.91.63.134-20150920063835/@comment-25507520-20151001141947

I'm with Neithan on this one. If the Emperor had known the extent of the Tyranid threat, I doubt he wouldn't have told the Legions about it. However, the way I can see Sanguinius justifying his side is if the Emperor knew about them, but said "Eh, i'll put them off for later... Oh crap a rebellion."

If he simply said they weren't that big of a threat at the time and would tell them when the real Hive Fleet got into the galaxy, then Sanguinius is right. But he kinda never got the chance, you know, with almost dying and all.