Wyatt Earp, from Martian Dreams
Earp was one of the humans whose bodies were taken over by the Martians who had fled to the Dream-World to escape the plague unleashed by Raxachk. While trapped in the dream realm, his body was taken over by the martian naturalist, Xichak.
The Avatar first met Earp in his dream, wherein he was a horse named "Marshall," and was up for auction, along with the horses Pistol and Smith. Ike Clanton was one of the bidders, and the Avatar had to bid against Clanton to finally win Earp's freedom, and restore his body to him.
Earp, a genuine American folk hero, was a noted frontier lawman, serving as a policeman in Wichita, Kansas and later as assistant marshal in Dodge City. Moving to Tombstone, Arizona, Wyatt, his brothers Virgil, Morgan, and James, and Doc Holliday found themselves feuding with the Clanton and McLaury brothers (cattlemen who augmented their earnings by rustling). The feud escalated into all-out war on October 26, 1881, when the Earps and Doc Holliday gunned down Billy and Frank Clanton and Tom McLaury in what came to be known as the Gunfight at the O.K. Corral. Earp was acquitted by the courts. My experience with Mr. Earp was limited (and, from what I know of him, I must say that doesn't displease me).