Lost Primarchs

Overview
The background leaves two additional unnamed and undescribed First Founding Legions, Legions II and XI. In some literature the missing Primarchs and their Legions are listed as being "Deleted from Imperial records". Earlier sources less ambiguously go as far as saying information on the Legions was deleted following the Horus Heresy.

The only information Games Workshop has ever released that directly addresses them, can be found in False Gods and The Lightning Tower (Dan Abnett). This has given way to the theory that II could possibly be the founder of the Blood Ravens chapter. This theory, however gives undue importance to the Blood Ravens, because, outside of the Dawn of War games, they are in no way a significant Chapter. This theory also does not describe why the Blood Ravens would be allowed to be still around in the 41st Millennium - obviously their forebears had committed some terrible acts of treachery for their records to be completely destroyed, to such an extend that even other Legions present at the time presumably also had any of their own records of the lost legions destroyed or modified.

XI
In the Black Library Horus Heresy novel series, Horus, in a chaos-induced dream sequence, apparently goes back in time and cracks the incubation capsule of Primarch XI before the Primarchs are scattered to the warp (the effect this has on the Primarch is inconclusive). Before doing this, he puts his hand on XI's capsule and feels "the untapped glories that might have lain ahead for what grew within, but knowing that they would never come to pass".

II
In the audio book The Lightning Tower by Dan Abnett, Primarch Rogal Dorn while constructing the defenses of the Imperial Palace on Earth in preparation for the coming attack by the Traitor Marines is walking through the palace and comes across a corridor showing statues of all 20 Primarchs. The audio book states that 'an accident befell them that may somehow be a precursor of what happened to Horus'.

In the novel Mechanicum it is described that "They are lost to us forever"

This could somehow point to the fact that the Blood Ravens have no real memory or information about their early history.

So the statement, "They are lost to us forever", could actually mean that their history or who they are are lost to us forever. Although another point to make is that the general opinion of the Blood Ravens being the one of the lost is incorrect and that Games Workshop will never reveal who the lost actually are. In any case, it is unlikely that the current writers at Games Workshop could do justice to the great mystery of what happened to the lost legions and why they were deleted from historical records.

Games Workshop's explanation
However, Games Workshop has explained the game play purpose for these "deleted" Legions: they are available to help those who wish to develop their own, custom Legions. The basic idea is since there were 20 Legions, and half went to Chaos but half stayed loyal, that these two lost Legions would represent the same for "do-it-yourself" forces. [[Category:L]]