Curse of Decay

The Godswar curse of the Grey Marches suffuses the Sphere with Necrotic Energy that comes from the Necrowells that come and go across the landscape. While the necrotic energy poisons and degrades the living, it does protect the sphere from the Maelstrom protecting souls and raising their corpses.
 

Astrological Effects

While the Grey Marches are in the sky magics that use necrotic energy are easier to cast and can be heightened. Unhallowed corpses may be raised by the with Necrotic Energy, and the hungry dead or other necromantic powered creatures become more feral and lose control of their hungers. Certain varieties of Were creatures are driven to destruction during this time.