Though he is a source of fear and revulsion to his enemies, Nurgle is a perversely paternal god, generous with his foul gifts and proud of his worshippers' every disgusting achievement.
Nurgle wishes to see rot and contagion bloom across the Mortal Realms, drowning the bastions of his enemies in a tide of putrid filth. Yet Nurgle is not malicious -- far from it, the Plague God delights in fecundity, and the overabundance of life that disease and decay brings. To Nurgle, every raddled corpse is a welcoming nursery for wriggling maggots and cloying plague spores. Every stagnant lake and rotting forest is a paradise in which parasitic larvae and bountiful poxes can flourish. These are the gifts that Nurgle lavishes upon the Mortal Realms, and if there is malice behind his generosity it is directed only at those ingrates who try to decline his offerings.
Nurgle's physical aspect is truly hideous. He is a swollen mountain of blubber and pus, whose necrotic flesh crawls with buboes and seethes with lice. Filth and foulness drool from the rotting maws that dot his corpulent mass, and flies the size of boulders buzz around him in thick clouds, drawn by his stench.
Since time immemorial, Nurgle has been in competition with his siblings, the other Dark Gods. In their great game, Nurgle is typically ranked third most powerful behind wrathful Khorne and duplicitous Tzeentch. Yet this is a misleading notion, for in truth Nurgle is in no way inferior to his brothers.
Rather, his might surges and recedes in a never-ending cycle. When plague and pestilence run rampant, Nurgle becomes so swollen with power that his leathery hide struggles to contain it. When remission comes, and Nurgle's plagues fall fallow, so his power wanes until he becomes a hollowed out shadow of his former greatness. Yet Nurgle is never defeated for long, for disease and decay are as inevitable as time and tide.
Nurgle has a far less fraternal relationship with the Horned Rat, the verminous Skaven deity who joined the Chaos pantheon at the fall of the World That Was. As an architect of plague and pestilence, the Horned Rat seems a natural ally of Nurgle, and certainly the two gods find common cause on occasion.
Yet where Nurgle wishes to spread bilious life, the Horned Rat seeks only the ruin of all, with no thought for new life or creation. As a result, Nurgle looks down on the vermin-god as short-sighted and distasteful, more of a means to an end than a true ally.
When the Age of Chaos began, Nurgle set his sights upon the inexhaustible cornucopia of Ghyran. His armies spilled accross the Jade Kingdoms, corrupting everything in their path. Thousands of mortal tribes turned to Nurgle's worship in order to save themselves from his countless plagues. The sylvaneth and their queen, Alarielle, were driven into hiding, and for a time Nurgle stood upon the very cusp of victory. Yet at last, an alliance between Sigmar's Stormcast Eternals and the resurgent sylvaneth defeated Nurgle's greatest champions. Alarielle sealed the Genesis Gate, through which the greatest portion of Nurgle's might had flowed into Ghyran.
For a time, Nurgle wallowed in the despondency of rejection, and as he did so his armies were driven back on every front. But now the Plague God's optimism has returned, and with it the realistation that - in obsessing over the conquest of Ghyran - he was being selfish. All of the Mortal Reams deserve to benefit from Nurgle's generosity, and he means to make sure that they are all showered with his blessings until they can take no more.
The Garden of Nurgle
The Garden of Nurgle is the Plague God's domain within the Realm of Chaos. It is a festering amalgam of jungle, forest, swamp and ornamental parkland in which unclean life seethes, and sickness blossoms with epidemic intensity.
No living being save a worshipper of Nurgle could hope to survive within the Plague God's garden. Its winding paths run with diseased slurry and squirming worms, while the air is thick with miasmal fumes and the constant drone of flies unnumbered. Groves of Feculent Gnarlmaws justle with bloated fungi and stinking fever-blooms. Sickly light spills from floating spore-sacs that drift through the murk, trainling slimy lianas with pus-fat thorns. Everywhere mucus drips, insects scuttle, and nauseating gases bubble and pop. Fountains of mouldering bone rise from congealed lakes Fountains of mouldering bone rise from congealed lakes, jetting putrid slop from squealing sphincters. Meadows of grass like rusted blades creak and groan in the languid breeze, spewing clouds of seeds that would rot mortal flesh in seconds.
As Nurgle's power ebbs and flows, so the boundaries of his garden realm expand and contract. When his might is at its peak, the Garden of Nurgle bursts its existential bounds and surges into the territories of the other Chaos Gods. Plains of fire-blackened skulls and fractal crystal mazes are swiftly overrun by the Garden's predatory fecundity, turning all to bountiful filth.
The Chaos Gods are ever at war, for they fight as only immortal brothers can. Each maintains countless armies of daemonic soldiery with which to defend their own domains, while invading those of their brothers. Nurgle is no exception to this trend, and his garden teems with the commaders and foot soldiers of his daemon legions. Patrol bands of Plague drones thrum along the garden's myriad paths, seeking invaders to torment. Tides of diminutive Nurglings scamper through the foetid underbrush intent on mischief, while packs of slug-like Beasts of Nurgle slither and lollop amidst the marshy pools searching for unfortunate playmates. Fortresses and guard towers oif rancid blubber and corroded iron loom over seeping gallows-trees, garrisoned by Plaguebearers who watch for hardy interlopers to punish.
At the heart of the garden stands Nurgle's Manse. The Dark God lumbers about this suppurating fastness, whistling phlegm-thick tunes as he gathers ingredients for his latest plague. Each new malady is brewed to perfection in his immense cauldron and then tested on the cursed creature knows as the Poxfulcrum, a caged being that has endured millenia of misery as Nurgle's personal test bed. Only once he is satisfied with the results of his concoction does Nurgle upend the cauldron, raining new contagions down upon the Mortal Realms.
- Hammerhal (Novel) by Josh Reynolds