[Kromm]

Another, more traditional addition to the collection of undead masters ruling over mortals and playing politics among themselves is the phony undead master. This person alters their appearance, scent, and even supernatural aura via some sort of magic, in order to appear undead. They raise zombies, ban holy water, tear down temples, banish priests, decorate their lair with creepy Gothic stuff, alter local statuary and written archives to support crazy stories about them being someone who died 500 years ago, etc. And they use the fear generated by their fake undead status – and likely real and very powerful magic – to control the locals. If heroes show up looking to exorcise ghosts, stake vampires, and so on, they might find themselves unprepared for the true danger (especially if this person can just switch off the disguise and show up as a random villager . . .).

Plot twist: Nobody said this person was human. They might be the member of some long-lived, unnatural race (faerie, squidfaced brainsuckers, extraterrestrials, ultraterrestrials . . .). That could really mess up the plans of fearless vampire killers.