Night Plague was a terrible disease that was used by the Usij, necromantic followers of the Osirian Pharaoh of Forgotten Plagues in -3064 AR to wreak havoc among the royal houses of Jistka Imperium. The Usij captured a Jistkan efreeti commander and transformed him into a ghul. They infected him with the terrible disease, which the enslaved efreeti traitor took back to his homeland. The deadly Night Plague specifically affected only the members of Jistka's royal houses. When the nobles were beset with the plague, it was a matter of time before their previous feuds re-emerged amid the chaos, leading to the downfall of the Jistka Imperium which was collapsed three centuries later.
- Wolfgang Baur, Adam Daigle, Jeff Erwin, and F. Wesley Schneider. (2012). Lost Kingdoms, p. 3. Paizo Publishing, LLC. ISBN 978-1-60125-415-3
- Wolfgang Baur, Adam Daigle, Jeff Erwin, and F. Wesley Schneider. (2012). Lost Kingdoms, p. 37. Paizo Publishing, LLC. ISBN 978-1-60125-415-3
- Alex Greenshields, Amanda Hamon, Jonathan H. Keith, Ron Lundeen, and David N. Ross. (2014). Osirion, Legacy of Pharaohs, p. 4. Paizo Inc. ISBN 978-1-60125-595-2