Mortarion: The Pale King

The Galaspar System was ruled by the Order, a regime that worked billions to death for its own profit, until the Imperium sent Mortarion and his newly claimed Death Guard to end it. The campaign was so savage that it shocked the Imperium itself. Now two of his fellow primarchs have come to Galaspar to make him answer for it, and the Pale King has no intention of apologising for how his scythe falls.