This was originally going to be a bit of the Makatiel, Demon Prince of Disease writeup that I… well. Water under the bridge. Anyway, here it is.
Contagion
This group spawned after the death of Makatiel (Prince of Disease) in 1348 AD, and has grimly held on ever since. Its members were and are former Servitors of Disease who traded most of their freedom and dignity to Saminga (Prince of Death) in exchange for continued existence, and each and every one of them bitterly resents the trade. Seven mortal centuries have not been enough time to integrate them fully into Saminga’s service; even the Orphaned Word-Bound Servitors of Disease are distinctly considered second-class servants in the hierarchy of Death. So it was inevitable that these quasi-Outcasts would eventually form a society dedicated to recovering their former glory.
It is not entirely clear that Saminga is unaware of this group; or that, even if he did know about them, he would particularly care.