Horus Heresy - Journal Tactica: Isstvan V, Part 1

As the Imperium expands its reach to uncharted worlds, a flourishing empire on the verge of ultimate triumph, the galaxy suddenly descends into an Era of Darkness. Horus Lupercal, the ruthless Warmaster of the Emperor's armies, has turned against his own creator. The eighteen Space Marine Legions, once allies in a Great Crusade to unite all of humankind under the Emperor's flag, are now divided by treachery. This is the Horus Heresy - the most brutal conflict in human history, a galactic civil war where genetically-enhanced soldiers clad in advanced armor wield devastating weapons against their former brothers. Where will your loyalties lie in this fight for survival?