Spoilers: The doctor’s bargain and his campaign plagues; no laboratory outcome and no campaign ending.
Who he is in Total War
Festus leads the Fecundites, the Nurgle-aligned Warriors of Chaos faction in Champions of Chaos. He shares that pack with Azazel, Valkia, and Vilitch. The campaign can be played in Immortal Empires or in the Realm of Chaos, and it does not follow Ursun.
On the field he is a Lore of Nurgle caster who also works through potions. Healing Elixirs restore his own fighters. Harbinger of Pestilence harms the enemy. The introduction is explicit that the two are mutually exclusive: one of them is active, not both. His army's plagues last longer, and the battle-healing cap of that army is raised. Vassals gain poison and spread Nurgle's corruption. Souls come in when a plague spreads.
The bargain and the ingredients
Both the store page and the July 2022 introduction start from the same life. Festus was a skilled, overly compassionate doctor. He traded soul and sanity for the knowledge to save others, and pledged his service to Nurgle for that forbidden learning. What remains is a devotee whose studies are sickness, ailments, and plagues. The introduction's warning is practical: better to die on the battlefield than to be taken for the experiments.
He still brews, and the store page separates his method from the daemons. He has to gather ingredients by routes his daemonic counterparts do not use. The concoctions are not described as weaker for that. The campaign page is where those ingredients become a plague for the next war. Ku'gath, the base-game Great Unclean One, invents diseases as a greater daemon and can hold many Blessed Symptoms at once. The 2022 design note used that contrast on purpose: Festus had to be more than a smaller Ku'gath. The answer they printed is the mortal doctor, the toggle between heal and harm, and a warband that is not the Poxmakers.
Other hands on Nurgle's work
Tamurkhan carries a maggot in a borrowed body and collects chieftains. Epidemius counts infections as they travel. The Glottkin are three brothers on one spawn, and their Gardens of Corruption are a different gate into daemonic units. Festus does not replace any of them. A Fecundites campaign that conquers the Empire is that campaign. It is not an End Times advance on Altdorf.
Update 9.0 puts him on Archaon's subjugation list. Beat him as the Everchosen and he can join that faction, with the Fecundites confederated because he is already Warriors of Chaos.
Festus the Leechlord: gameplay and availability · More character stories
Sources
- Introducing Festus the Leechlord — Total War — totalwar.com
- Champions of Chaos — Total War — totalwar.com
- Addressing the Chaos Debate — Total War — totalwar.com
- Immortal Empires DLC Ownership Guide — SEGA — support.sega.com
- Patch 9.0.5 notes — store.steampowered.com
- Update 9.0 release notes — community.creative-assembly.com
- Champions of Chaos — store.steampowered.com