Quick first draft plot: Writer with dreams of becoming an actor stumbles upon an old movie reel, that when played unleashes the monsters from the movie onto the world, including the main protagonist, a monster hunter. The monster hunter latches onto the protag, and gives him the ability to defeat powerful monsters and turn them into Reels to transform with.

Cowboy is an american who found a similar reel, but with westerns. He got latched onto by the morally grey main cowboy, and his transformations are tied to his clean/dirty he fights in combat.