Western is a genre literal for western stories. He looks very similar to John Wayne from the Western movies. He can sense Bigby's actions, because they both are sheriffs. He likes to play cards (possibly poker) alone. He was called upon by Kevin; who was under the influence of Writer's Block. However, he still found even with the genres here, that they were boring. Bigby, Snow, Gary, and Mister Revise; along with the Page Sisters, had come to stop him from doing further damage to reality. Kevin sent the Genres, including Horror to guard his house and fight off the others.
Bigby, who had been put through much humiliation and transformed into a girl to further it, lost his patience. While Robin, Priscilla, and Hillary fought off the others, he snuck around trees and attacked all the Genres. Horror was the first to see her (Bigby who was still stuck in his little girl form) and immediately ordered the others to kill her(Bigby). Quoting the sweeter they are, the more danger they are; since she spoke from personal experience, given her appearance.
However, Blockbuster and Western refused, as it was a rule not to kill a little girl, especially a child. That would be a mistake as Bigby would show no mercy and kill Western and the rest of the Genres. For the moment, after defeating Kevin, Western and the rest of the Genres had apparently recovered. Or it meant they were resurrected by Kevin or simply replaced. They were all sent into a new world where Kevin could do what he want and leave the mundy world alone.