Brock is the first Gym Leader faced in the original Pokémon games.
He leads the Pewter City Gym in Pokémon Red, Green, and Blue, making him the first major Gym challenge in the Kanto adventure. Brock specializes in Rock-type Pokémon and awards the Boulder Badge when defeated. His team includes Geodude and Onix in the original games.
Misty is the next Gym Leader, leading the Cerulean City Gym and awarding the Cascade Badge. Lt. Surge follows in Vermilion City, while Giovanni is the final Gym Leader encountered in the standard Kanto sequence. These characters are therefore easy to mix up when recalling the early badges.
Brock also became prominent in the anime, where he travels with Ash for much of the early series. The game character and anime character share the same name and basic identity, although their stories, dialogue, and teams are not identical in every adaptation.