Gym Leader

Gym Leader (Japanese: ジムリーダー Gym Leader) is the highest-ranking member of a Pokémon Gym. The main job of a Gym Leader is to test Trainers and their Pokémon so that they are strong and resourceful enough to take the Pokémon League challenge. If a Trainer defeats a Gym Leader in battle, then the Trainer earns that Gym's Badge.

Gym Leaders are also responsible for overseeing how their respective Gym is run and maintain it. Great care must be taken to make sure that their Gym reflects the best environment for the type they specialize in, such as swimming pools in a Water-type Gym or trees and flowering plants in a Grass-type Gym. According to Morty, teaching young people how to battle with Pokémon can also be the job of a Gym Leader. Unlike regular Pokémon Trainers, a Gym Leader has the right to directly challenge the Pokémon League Champion, as revealed by Brock in [https://bulbapedia.bulbagarden.net/wiki/Pok%C3%A9mon:_Let%27s_Go,_Pikachu!_and_Let%27s_Go,_Eevee! Pokémon: Let's Go, Pikachu! and Let's Go, Eevee!].

It has not exactly been made clear how Gym Leaders attain their position, but it appears that it varies for each Gym. Some of them founded their Gym and are self-appointed; others, such as Whitney, are chosen by the other members of the region's Pokémon League. A few appear to be passed on through families: Janine, Falkner, and Flannery all take over their respective Gyms from a close family member. However, Gyms do not necessarily belong to a particular family; Roark and his father Byron are both Gym Leaders at the same time, in different Gyms. Leaders can also choose to vacate their position; examples include Koga, Giovanni, and Wallace.

Pokémon used
Nearly all Leaders rely on a single type of Pokémon. For example, Erika uses only Grass-type Pokémon in official Gym battles. Some Leaders, however, stray from this mold, albeit rarely. This is evidenced by the different types used by Blue during his reign as the Gym Leader of the Viridian Gym in Generations II, IV, and VII, although he is the only Gym Leader to do so. However, many Gym Leaders have one or two Pokémon that stray from their type theme.

Geography and climate can often be connected to the type of Pokémon the Gym Leader of that area uses. Pastoria Gym Leader, Crasher Wake, uses Water-type Pokémon, a direct allusion to the flooded marsh that surrounds the area and the constant downpour that plagues Pastoria City. Another example of this is the Cinnabar Gym Leader, Blaine, who uses Fire-type Pokémon and lives in a volcanic area.

The character archetype can also reflect the type of Pokémon a Leader uses. For example, Roark and Byron, who are both miners, use the related Rock- and Steel-type Pokémon. Tate and Liza could be based on the archetype of twins who can communicate telepathically, and thus train Psychic-type Pokémon and being twins, they also battle opposing Trainers in Double Battles.

In the core series
A Gym Leader (Japanese: ジムリーダー Gym Leader), or Leader prior to [https://bulbapedia.bulbagarden.net/wiki/Pok%C3%A9mon:_Let%27s_Go,_Pikachu!_and_Let%27s_Go,_Eevee! Pokémon: Let's Go, Pikachu! and Let's Go, Eevee!], is the Trainer class name given to the Gym Leaders when they are battled in the Pokémon games. Despite Gym Leaders themselves being introduced in Generation I, the Trainer class did not appear onscreen until Generation II, and it has been incorporated into every game since. Gym Leaders are integral within the Pokémon universe. Occasionally, in order for one to advance in the game, the player must challenge and defeat the leader of a Gym. Each game is designed in such a way that the player will not be able to move forward until they receive a Gym Badge which will, in turn, either allow them to use an HM to overcome natural obstacles or trigger a necessary event to continue with the game. It is one of the player's main objectives to collect eight Gym Badges, allowing them to challenge the Elite Four.

Leaders do not seem to be required to be in their Gyms at all times. Giovanni, for example, could keep his title as a Gym Leader despite not being at the Viridian Gym during the majority of the events of Generation I, and his successor, Blue, was also absent from the Gym several times. Beginning in Generation IV, Leaders are increasingly encountered outside of their Gyms, evident in the remakes Pokémon HeartGold and SoulSilver, where the Leaders have to be found in different locations at specific times before they can exchange phone numbers with the player for a rematch at the Fighting Dojo. Some Leaders even appear across regions, such as Jasmine appearing in Sunyshore City, Crasher Wake on Route 47, and Maylene in Celadon City. Leaders can even challenge other Gyms and the Elite Four (like Volkner wanted to do). In later games, it is made apparent that Gym Leaders know each other and are acquainted with Gym Leaders from other regions, as well as with members of the Elite Four and Champions. Examples of this are Jasmine being friends with Erika, Volkner being friends with Flint, Brawly training with Bruno, and most Unova Gym Leaders coming together to fight Team Plasma's Seven Sages.

In addition, some Gym Leaders may be required to use Pokémon different than their usual team, such as Cheren in Black 2 and White 2. Due to their higher AI compared to regular trainers, Gym Leaders are also one of the few Trainers to employ the use of Potions when battling.

Gym Trainers
In addition to Gym Leaders, there are also Gym Trainers. They are Trainers that are either a devotee or apprentice to the Gym Leader, who follow the same type theme as the Leader does. It is usually necessary to defeat multiple Gym Trainers before challenging the Gym Leader. Some Gyms in the game require the player to solve a puzzle, and one must often use Gym Trainers as obstacles to reach the solution. They have no direct impact on the overall plot, other than rarely offering the player helpful advice. It is also worth noting that the type of Trainer appearing in a Gym will depend on the Gym itself. For instance, Gardenia employs Aroma Ladies and Beauties, exclusively, while Misty recruits Sailors and Swimmers; these Gym Leaders represent the types Grass and Water, respectively. However, starting in Generation VIII, they only have the Trainer class "Gym Trainer", as well as a special introduction featuring their Badge.