Epidemius, the Tallyman of Nurgle is a Plaguebearer that is one of the seven Proctors of Pestilence. He is Nurgle's chosen tallyman that must catalogue all of Nurgle's diseases, an unending task that generates a lot of paperwork, which is why he rides on a palanquin.
As a plaguebearer of nurgle he is disgustingly resilient which allows him to ignore even grievous wounds.
When he goes into battle he has a Balesword in one hand and a hourglass in another. He keeps tally of the diseases on the battlefield, enumerating them on a parchment of cured-flesh using a bone quill and, as he records those slain by it the servants of Nurgle become more powerful.
Epidemius' Palanquin is a mouldering wooden seat that carries many trophies, from fleshy skulls at the bases to the shields, banner and ichor-soaked bell at the top. This palanquin is carried by a suppurating mound of subservient Nurglings that can attack nearby enemies with their tiny teeth.