Lupercal's War: A Horus Heresy Anthology

Never has the Imperium known a weapon as deadly as the massed might of a Space Marine Legion. Together, these mighty warriors form an unbreakable spear at the forefront of the Great Crusade. Together, they quest to reclaim humanity's birthright – its dominion over the stars. Each Legion is led by a legendary primarch, and the greatest among them is Horus Lupercal, Warmaster of the Imperium. Yet at the height of his power, this beloved son betrayed his oaths, taking half his brothers with him into damnation.