Festus the Leechlord

Festus the Leechlord is the Dark Apothecary, the Fecundite, and a servant of Nurgle.

Overview
If an unfortunate traveller were to stray onto the twisted roads that lead from the northern forests into the Chaos Wastes, he might be paid a visit by a most unsavoury individual during the dark o f the night. A shuffling, muttering figure stalks these lands, his moth-eaten robes gently clinking with vials containing unimaginable concoctions, which he is seeking to test out upon those he can catch or deceive. A devotee of the plague god Nurgle, this mysterious apothecary is quite, quite mad, though he once bore the respect o f physicians, alchemists and scientists across the length and breadth of the Old World.

Doctor Festus was once a skilled chirurgeon who founded hospices all across the province of Nordland, and was as compassionate as he was gifted. Specialising in curative unguents and salves, the good doctor cured hundreds o f people every year. With Festus’ guidance, Nordland overcame outbreaks o f the Screaming Ague, Blacklegge, and even the crippling Ghoulpox.

It was the onset of Gnashing Fever that marked the beginning of the end for Festus. Try as he might, the doctor could not stem the spread o f this new and highly contagious disease. Festus locked himself in his laboratory, working ceaselessly to create a healing elixir. Coundess sleepless nights passed, and despite his best efforts, Festus still had no cure.

Those plague victims he had managed to sequester in his laboratory were dying and he was powerless to prevent it. As the last o f his test subjects shook themselves to death, Festus dropped to his knees, crying out for help. O ne by one, the slack-jawed corpses in Festus’ laboratory turned their heads to look at him. With one voice emanating from a score of parched throats, they promised to give Festus the knowledge necessary to cure not only this plague but all the diseases in the world, in exchange for a lifetime o f service. In his desperation, Festus agreed.

In the blink of a bloodshot eye, Festus’ mind was filled with every detail of every sickness, ailment and plague known to the great god Nurgle. This drove him entirely mad, washed away his compassion and left nothing more than an intimate knowledge of disease and a desire to experiment. Festus became the Leechlord of Nurgle, who goes to war in the name o f furthering his revolting studies. Though his curative powers are greater than ever before, woe betide the fool who crosses the Doctor, for he is always in need o f new test subjects, and not above force-feeding his latest concoctions to his victims in his quest to bring ever more repugnant forms o f life into the world. It is a better fate by far to die on the field of battle than to be captured alive by Festus and used for his latest dark experiments.

Source

 * Warhammer Armies: Warriors of Chaos (8th Edition) -- pg. 42