To the people whom haven't yet posted characters. Can I get a quick 3-4 words that generally give me the just of your Primarchs? Just to avoid potential overlap.

So far I have Vellian Barbas, Primarch to the Doom Guard (Subject to change) he grew up on a swampy death-world. 

Doom guard - Shock assault tactics, Blitzkrieg, quick precise strikes more often than not at opponents blind spots.