For centuries, the worldship Solarvoid has roamed the cosmos. The might of an entire civilization contained in a colossal craft, a titanic triumph of science, engineering and culture, traversing the eternal night of space. But now, an ancient and monstrous evil stalks the ship. A sinister cult performs bizarre rituals in the half-forgotten bowels of the Solarvoid. Intrigue, suspicion and murder haunt even the mightiest of Great Houses. War is coming. A war in which the courage and technology of humanity will be tested to the limit… against the forces of Hell itself.

https://www.amazon.com/dp/B07SKKCV1F