Devourer

As war rolls across the Cryptus System, Blood Angels Sergeant Jatiel and his squad are far from the fighting, standing sentinel over a dead world. Across the galaxy another threat rises as the necron overlord Anrakyr the Traveller seeks to awaken a tomb world – a goal that will ultimately lead him into the heart of the battle for the Cryptus shieldworlds and a desperate alliance with the sons of Sanguinius.

Read it because
The battle for the Cryptus systems reaches its climax as Xenos both newly spawned and incomprehensibly ancient clash. In this warzone, even the most bitter of rivalries are set aside in the face of utter destruction. The necrons make great antagonists, but here we have one of only a handful of titles where we see war from the perspective of these ancient warriors.