Epidemius

Epidemius is Nurgle's Tallyman, the Plaguebearer Herald who records every infection, death, and interesting rash as if the Garden might otherwise forget. He rides a palanquin of Nurglings with an endless scroll and a patience that outlasts civilisations. Where he disembarks, the statistics get worse on purpose.

He does not need to win a battle if the after-action sickness will do it. Imperial seers hate him because a named accountant is harder to dismiss than a nameless fog. Nurgle loves him because someone is finally doing the paperwork.

The tally is never finished. That is the joke, and the weapon.