Board Thread:Warhammer 40k General Discussion/@comment-6078851-20130318203252/@comment-3258762-20130327163322

Actually it is proven several times that one of them is dead, and amongst all legions it is speculated that the Wolves were used to bring down the Legion, but the latter part is, as they say, speculation.

Dorn once slapped Fulgrim for breaking his oath to never mention the missing Primarchs and banished him from the Phalanx after Fulgrim said that "I believe our lost brother was killed by Russ" (Some short-story, not the HH series, so it could be wrong, think it was part of a magazine)