The game contains 107 new Pokémon and chronicles the adventures of a new Pokémon trainer who strives to become the Pokémon League Champion, collecting and training various species of Pokémon along the way.[3] As do most games in the series, Diamond and Pearl feature eight Pokémon gyms led by Gym Leaders, professional trainers whose expertise lies in a particular Pokémon type. Gym Leaders serve as bosses and reward skilled trainers with badges of merit, key to the advancement of the plot.