Invasion of the Dopperglangers

a normal world, or something like that, when {Protagonist} says /Start/ the slow invasion of Doopperglangees or face-stealing beings will begin, who copy the appearance of people or animals but with some deformities, first the invasion will begin with news of disappearances and about intruders or murderers, that will be "Stage 1", then the quarantine will begin for security since it is feared that there are deformed intruders who use the appearance of others but not so well since they always have something different, that is "Stage 2", "Stage 3" is when those creatures come to light and begin the chaos and destruction, then "Stage 4" will begin which would be a world with ruined cities and plants, where survivors will fight to survive and will not trust anyone for fear that someone is a Doopperglanger, after this the last stage begins, "Stage 5" where the human will be almost extinct and the last will begin the resistances thanks to the knowledge of the {Protagonist} since he remembers by heart the bestiary (creature book) that his grandfather gave him and now they know the weaknesses and more of the Doopperglanger and the other creatures apart from those expensive clothes