router.patch(CharacterContent.self, at: "characters", Character.parameter) { req, update -> Future<Character> in
    let character = try req.parameters.next(Character.self)
    return character.map(to: Character.self) { character in
        character.name = update.name ?? character.name
        character.age = update.age ?? character.age
        character.title = update.title ?? character.title
        character.allegiance = update.allegiance ?? character.allegiance
        return character
    }.update(on: req)
}