Supernatural Western books are a fairly new genre that originated from the urban fantasy genre — a subgenre of the Western genre, which was popularized in the United States by Owen Wister's novel "The Virginian" in 1902.
The supernatural western has been gaining popularity in recent years, with more and more authors writing in the genre. The supernatural western typically features a protagonist who is a gunslinger or lawman who fights against all kinds of monsters, from ghosts to witches, vampires, werewolves and zombies.
In this genre, there is usually a mixture of fantasy, horror and mystery (sometimes steampunk), in addition to traditional western elements such as cowboys, sheriffs, outlaws, lawmen and gunfights. The stories often involve tales of revenge that can be attributed to Native American beliefs or European folklore that have been passed down through generations.
One thing you can be sure of --- there's going to be a lot of action!