A purchased module is used as the seed for creating a Game, and will set it up with all of the initial details of the model. If the creator of a Game is a Pro Subscriber, they can use the Transmogrifier to copy individual pieces of content (Map Pages, Characters, Handouts, Rollable Tables, etc) from that game to other games they have created. Anyone that buys a module can create a Game from that module as a starting point for building a homebrew game. If all you want are characters, the Character Vault can be used to copy characters from a module Game to a homebrew Game.