Tamurkhan
Tamurkhan the Maggot Lord is a Chaos Lord dedicated to Nurgle in Warhammer Fantasy Battle. He is the titular character of Forge World's Tamurkhan: Throne of Chaos campaign book.
Tamurkhan's moniker is no mere affectation; thanks to a unique gift from Papa Nurgle, his true form is a pestilent, slime-dripping maggot-thing the size of a human child, which can bore into living victims and devour their guts, then take control of the corpse as a secondary skin. Through this manner, he has achieved a twisted immortality, allowing him to fight inside a corpse-host, then attack and possess his opponent (or a living ally, if shot down from afar) to keep on fighting when it is destroyed.
During the events of Throne of Chaos, Tamurkhan wore the corpse-hosts of first Sargath the Vain, a Chaos Champion of Slaanesh, and then the Ogre Tyrant Karaka Breakmountain. In both forms, and countless more before, he rode Bubebolous, a Toad Dragon with +1 WS, +1 Strength and the Mark of Nurgle. He fell at last when he tried to take the body of Theodore Bruckner, only for the Baleflame Amulet gifted to him by Magisterix Elspeth von Draken to perform its deadly task; immolating slain Imperial champion and Chaos-get abomination in one fell surge of arcane flames. Thus perished Tamurkhan, and ended his pursuit of the Throne of Chaos.