Since the pistol belongs the the tribe's chief, maybe Greyback could be
the main character in a sequel, and if you use that new formula, the humans
have to become the villains for the audience.
How about the US cavalry or any other historical opponent raiding the Comanche
village, the flintlock pistol is taken by the main vilain, and Greyback hunts 'em down.
What are your ideas.