Templar Bases are enemy structures in Plague Inc.
Templar Bases are fortified military outposts reinforcing each other over time against the Vampire threat. They will also assist cure research if possible.
Templar bases will become stronger over time - You might have to purchase Shadow Blades for Blood Rage to have sufficient strength before the Vampire gets depleted as otherwise you'll rely on lairs and Dark Ritual.
If you can't deplete its health, bases will also fall if Shadow Slaves has been evolved with too many infected in the country, or if the population dies out, whichever comes first.