Welcome to part two of my rinky-dink series on what I've learned from brief research about ghouls, revenants and zombies. You can click here for the section on ghouls.
Having a revenant sounds cool, but Wikipedia defines it as a ghost or an animated corpse similar to a vampire* so not sold.
In some folklore, it's a person who returns to harass neighbors and family*. Nothing special, like another ghost there.
I do like the other definition it offers: a dead hero brought back by a wizard to go on some quest no one else would brave, under the wizard's control. It also referenced Jason (Friday the 13th) as a revenant, and the protagonist of The Crow. Side fact: I have never actually seen that movie.
My experience with revenants has been through the Final Fantasy series, a stronger version of a zombie (causing life-drain when it attacked. Like a vampire, if I recall). They're mentioned as spreading disease among the living, which I could make use of.
I'm undecided on revenants.
*Taken from www.wikipedia.org