Brock is the rock type gym leader in pewter city and is one of the eight gym leaders in kanto. When beating Brock you get the Boulder Badge; you need all eight Badges to battle a against the Elite 4. Brock is a good trainer and takes care of his pokemon... also, he is a pokemon breeder
Brock's Geodude is a strong and sturdy pokemon who, dispite his hard look, he is soft on the inside and helps brock with taking care of other pokemon.
Onix is brock's strongist pokemon and is his ace in the hole. Onix uses its giant tail to slam its enemies and will burrow under them to either throw them into the air or bite them.
Rhyhorn is one of Brocks pokemon and is rarely used in the gym. But when it is its a challnge to beat. It uses it strenth to charge at it enemys and slam them across the room and will shoot rocks at them to finsh them off
Kabutops is ancient pokemon that was recovered from a fossil by the scientists at the Pewter city museum. Kabutops relies on its speed to take now its enemy and uses its two blades to cut them down easily