User blog comment:Dantioch/Blood Ravens - Thousans Sons/@comment-24226187-20160220020132

There have been speculation on behalf of the inquisition who found of disturbing interest the ways of the Blood Ravens, their absolute zeal for the preservation of knowledge, coupled with the high number of psykers among their ranks could indicate a possible relation with the now traitor legion of the Thousand Sons, though there is no definite proof to validate these claims the inquisition had been force to stand down and keep their eternal vigil on these sons of the emperor waiting for the chance to condemn them into eternal oblivion.

Another disturbing evidence that further shadows the truth is the apparent lack of information regarding the Blood Ravens origins even though their zeal for knowledge belays those claims yet again it only serves to vail the truth.

In retrospect not every fellowship was present during the Burning of Prospero even the mightest Gloriana-class vessel of the Thousand Sons, Photep, was also missing among the ranks of the thousand sons at the apex of the Battlefield. Where such vessels went or with what purpose they serves even whose master the respond to, are all shed in lies and specutations with no hard evidence to back them up. So the possibility of the Blood Raven sprung from one of such vessels is likely yet proof have either buried into oblivion or porpusely forgoten to ensure their loyalty to the Emperor.