Corvus Corax, Primarch of Raven Guard Corax and his legion had one of the Horus Heresy books dedicated to them. The first half of the book characterized him, his legion, and his doubts very well. Instead of taking a page from Lorgars book Corax doesnt give in and sulk. However, the second half of the book changes his characterization back to a brooding loner. Im not sure which is the real Corax, thus he ranks lower than he might otherwise.