Garro: Burden of Duty: The Horus Heresy Series

As the renegade forces of the Warmaster storm across the galaxy, a very different kind of war rages in the shadows of the Imperium - the Knights Errant, chosen of Malcador himself, move quietly in the dark places where others cannot. Battle-captain Nathaniel Garro makes his way to the Imperial Fists' mighty starfort Phalanx, seeking out another kindred soul for his elite band of warriors.