Epidemius is one of Nurgle's favorite plaguebearers.
Official Canon Edit
Epidemius' task is count the number of Nurgle's plagues and diseases that have spread, as well as coming up with new symptoms. He is an even more lazy bastard than most plaguebearers, having to be brought everywhere in a chair by nurglings.
TTS Canon Edit
Epidemius is in the middle of reviewing the new disease Crotch Rot when he is assaulted with bars of soap by Leman Russ and his posse.