Corax

I always love Corax the Primarch of the Raven Guard because he is a loner and one of the best at melee. He would have slain Lorgar at the Ivstann drop site massacre if not for the intervention of Curze. Of all the loyalist Primarchs at Ivstann Corax survived and slew many many traitors. I see him as a character of the silent rage and one who epitomized the tactic of See but don't be seen.