Board Thread:Warhammer 40k General Discussion/@comment-202.67.108.41-20140425072251/@comment-92.227.144.29-20140425221000

sons of antaeus> death guard might be likely

ultramarines did not take in legions from other primarchs, simple biology would complicate that (pass on progenoids from severals sources and mix em together)  think of introducing foreign tissue to a body, the autoimmune system would attack it.

and ultramar had 500 worlds, enough with guillimans's aptitude for governing to secure a very high "production" rate for the legion. no other legion had such a big recruitment base.

it is hinted that BR come form thousand sons but we could also taker others

knowledge is power:- BR

Information is voctory -ultramarines

it would simply not make sense to not use the  basis of all gene-seed for the next foundings

grey knights work on a different way: the first ones were taken from several legions, that is correct but they all received new gene-seed from a purer/superior source see "pandorax"  there it is only the case of taking individual psyker astartes with the right mindset aka loyal to da emprah