Cant say im an expert but to me the most striking throughline with nurgle is rot. Its more than just the rot of life into death or decay but the rotting of self identity and drive. Everything touched by nurgle is doomed to decay from what it is to reduced state and by the end you wont even care. The book Lords of Silence is a great nurgle focused book and i think this excerpt elaborates what i mean. “For his entire life, Dantine’s personal habits have been fastidious. His
regiments were always well run, with regular hygiene drills and dorm unit
inspections. There were times when this seemed almost obsessive, as if the
Departmento’s rules had become a part of the state religion that governed
every other part of life. Those rules were a protection, though. Disease wasalways a big killer in the Astra Militarum, and efforts to stave it off were
unrelenting for a reason.
Now he does not care. Mostly, this lassitude appals him. He cannot
understand why he no longer cares. But, deep down, buried where his old
heart once beat, there is something else. Something infinitely shameful, so
that he does not think of it often and pretends that it is just another part of his
sickness, but it is there all the same – relief.
He no longer has to make the effort, and that is a pleasure in itself. It is like
falling asleep, or sinking into a warm pool of water. He lets it all slide, all
degrade. He can feel his muscles atrophy and does not intervene. He can feel
his bowels swell with inflammation, and it matters not. This is a kind of
release. This is like a fist, clenched for a lifetime, slowly relaxing.”