Ash aspired to become a Pokmon master throughout the Pokmon series, so he naturally faced off against his fair share of gym leaders. Based on the boss-type characters from the mega-popular video game series, they came in all forms, with all types of personalities and interests, not to mention the different Pokmon types they specialize in. However, them all being gym leaders suggests they can put up a good fight in a Pokmon battle and Ash learned firsthand how often this is the case.