Who is the narrator, can she or he read minds, and, more importantly, can we trust her or him?
First Person / Third Person Omniscient
Since the Pardoner's Prologue is his description of the techniques he uses when he's on the road selling relics and pardons, he narrates it in the first person. When he launches into the narration of the tale proper, the narrative voice shifts to a third person omniscient one. It's a voice that's very much involved in its tale, though: the Pardoner lets us know what he thinks of the young men. The rioters' gluttony is "abhomynable," their oaths "dampnable" (185, 186). The Pardoner also interjects himself to take the Bible as his proof for various "truths," like the fact that "luxurie is in wyn and dronkennesse" (198).
The Pardoner's commentary on his tale even extends to the way he refers to his characters: not only does he refer to them as "the riouteres," and "hasardoures," but also "shrewes;" individuals become "the proudeste" and "the worste" – all of which are loaded terms with negative connotations. In the Pardoner's Tale, it's impossible to forget the narrator's commenting, judging presence.