The Viral Zombie Expansion to the Astulae Campaign Setting
From the introduction:
Astulae: Necrogenic is an expansion for the original campaign setting. Specifically, it deals with an outbreak of zombies caused by a virus within the Astulae that threatens to overrun everything. As such, it is both an extended campaign in and of itself with an adventure for PCs to take part in, and it is an expansion that includes new narrative strands for how the Astulae factions deal with the outbreak and respond to it.