Plague (Marvel)

Plague was a mutant who had the ability to magnify and spread disease and was apparently a Morlock. Plague was present during the massacre of the Morlocks by the Marauders and was terrorized by Sabretooth, who was unaware of her ablilites and left weakened and might have died if not for his healing factor. Apocalypse arrived and saved Plague from the massacre, stating that he had plans for her to serve him as the Horseman Pestilence.

After being transformed into Pestilence, Plague, War, and Famine battled X-Factor in Central Park and were defeated by Iceman. After the fourth Horseman, Death, was revealed, Apocalypse had the Horsemen battle each other, to find the leader and Death beat them all.

After Apocalypse teleported X-Factor on his Celestial Ship, they battled the Horsemen again and, after their defeat, the Horsemen were sent into Manhattan to incite chaos. X-Factor and the Power Pack battled the Horsemen and Lightspeed knocked Plague off her flying steed, whereupon she fell to her death.

Television History
Plague was a Morlock. She appeared as a woman wanting a cure and was transformed into the Horseman Pestilence.