Maledictus

The elite daemon-hunting Grey Knights arrive at the world of Squire's Rest, their prognostications showing that a daemonic presence will soon erupt upon the quiet planet. But their careful plans are disrupted by another threat - the Red Waaagh! that engulfs the Sanctus Reach has come to Squire's Rest. As the Grey Knights engage the savage orks, they find that their very presence may have set events in motion that will drown the world in Chaos.

Read it because
Lurking beneath the seeming greenskin menace of the Red Waaagh! is something deeper and darker… something only the Grey Knights can handle. A fascinating look at the interplay between the warp and other threats, and between the Grey Knights and Inquisition.