Board Thread:Warhammer 40k General Discussion/@comment-91.224.27.226-20131031140001/@comment-3258762-20131214120025

Or, you know, that Primarch is dead and the legion has been wiped out/absorbed into the Ultramarines. Also a possibility.

And the way I remember it, it was one Primarch who was censured and one who was never found. Both legions magically disappeared (Cough Space Wolves Cough Ultramarines Cough)