Board Thread:Warhammer 40k General Discussion/@comment-37.152.33.225-20131111163502/@comment-6078851-20131217135724

i think the lion is most likely to be the 1st returner because, as i mentioned, we know where he is and he's in perfect condition. vulkan is still a contender for the 1st returner because he chose to disappear and set conditions for his return, but no-one knows anything about his location or his health. for all we know he may be dead - primarchs (and astartes) are effectively immortal in terms of ageing but given that no primarch has lived for 10,000 years he may have even died of old age! (i don't believe that but it's a possibility)

as for vulkan being 'given' command of his chapter (mini legion), that wouldn't happen -  he was, is, and always will be the primarch of the salamanders and no-one can change that (without him turning traitor). if he returns the salamanders will simply welcome him back into his position of ultimate command.