Plague War Haley Guy (2022)

The second book in the Dark Imperium series. In the void and across the worlds of Greater Ultramar, the battle for the Imperium continues. Determined to rebuild his home realm and use it as a base for reconstructing humanitys ravaged stellar empire, the returned primarch Roboute Guilliman continues his war to drive Mortarion and his Death Guard Traitor Legion from the domain of the Ultramarines. But when Guilliman confronts his brother on the diseased plains of Parmenio, the intervention of a greater power in their fraternal struggle threatens to overturn the Imperial Regents understanding of the galaxy and his place within it. Primarchs and ideologies clash in this second part of the Dark Imperium trilogy.