Plague Planet
From Lexicanum
The Plague Planet is the Daemon World of the Daemon Prince Mortarion, and homeworld of the Death Guard traitor legion.
It is a world where disease is the norm and miasmic clouds bring contagion and death. Its diseased inhabitants pray to Nurgle for relief from their constant agony. Some of them are favored and become his Champions, and then fight among themselves for mastery and the chance to become Daemon Princes themselves.
Beastmen make up a large part of the population; they are bloated with disease and flies swarm around them and breed upon their rotting flesh. The beastmen are very proud of these signs of their god's favor, and openly boast of the number and severity of their diseases.
The Plague Marines involve themselves in carrying out Mortarion's wishes and traveling to other worlds to spread Nurgle's plagues.
All spacecraft which succumb to plague are eventually drawn, through the warp, to the Plague Planet, where they become part of the planet's fleets. These Plague Fleets carry followers of Nurgle through the warp to inhabited worlds where their destructive raids are inevitably followed by outbreaks of deathly contagion.
Mortarion has shaped the planet much as his homeworld, Barbarus. Its citizens cower in tiny villages, serving their supreme masters who reside in mighty fortress citadels far above all of them. There are creatures that should be dead and are diseased far beyond reckoning walking the planet. All is ruled by the skeletal Mortarion, enthroned upon the highest part of the planet, much like his false father was on Barbarus.
Because it is located close to the fabric of reality it is an excellent place to launch invasions and attacks from, especially against Imperial worlds.
