So reading the wiki's, and just general forum discussions over the years, there always appear to be some chapters who have flaws in their geneseed that don't match up with any parent chapter. Some also have a doctrine of combat, or a culture reminiscent of some particular Astarte forces that went all teenager on the Emperor.
Of course we have the Blood Ravens, whom some theorize could be founded using Thousand Sons geneseed.
Similarly, there is speculation that Minotaurs and Charchardons may have been created from Warhound and Night Lords geneseed.
We know that there are banks housing geneseed of the traitor legions on Terra, and that the High Lords sometimes try to "experiment" when founding chapters.
So what are all of yall's thoughts? Have Space Marine chapters been founded using the geneseed of traitors? Is it possible? Likely? Even accidental?
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And in honor of the History Channel:
Were some Space Marine Chapters founded using the geneseed of those legions who betrayed the Emperor? Ecclesiarchy and Inquisitorial agents say no; but our Traitor's-seed theorists suggest that this might be so.