Gary Oak

Gary Oak is Professor Oak's grandson and Ash Ketchum's rival in the first few seasons.

Background
Gary Oak (オーキド・シゲル), voiced by Yuko Kobayashi in Japanese and Billy Beach in English, is Ash's rival. Before he lost to Ash in the Johto Pokémon League, he was arguably the most arrogant character in the entire series, but since then, he has became more open-minded. He and Ash grew up together in Pallet Town and quickly became rivals after becoming Pokémon trainers. Before his loss against Ash in the Johto Pokémon League, Gary collected Gym badges and then competed in the Kanto and Johto Pokémon League tournaments, but since his loss he pursued a career in Pokémon research, impeding his rivalry with Ash.

Pokémon Strategies
Gary and Ash's techniques are like the North and South pole's of the world; while Gary spends his time raising his pokémon in good technique and teaches them tough and cool moves, Ash uses clever strategy during battle and teaches most of his Pokemon tough and smart moves; Gary's Pokémon endure tough training and do not rely on luck and love in order to win battles.

In the Games
The only game Gary is in is Pokemon Puzzle League, however his counterpart in the main series of games is Blue, who is Gym Leader of Viridian City in Gold, Silver, Crystal, HeartGold, and SoulSilver.

In the Manga
He has a counterpart in the manga named Blue (Green in Japan).

With Gary and at Oak's (anime)
and at least 13 other pokemon as seen in IL025

Trivia

 * In Gary's first appearance in Battle Frontier, Gary's new clothes resemble trainer Blue's clothes in Pokémon LeafGreen and FireRed.
 * In the Japanese Edition of the manga, Pokemon Special, Gary's name is Green.
 * Though, due to the fact that Pokemon Green was not released in America, his name was changed to Blue in the manga and games for the English release.
 * He has become less prideful and arrogant than in his earlier apearances in the anime.
 * Gary is the only one of Ash's rivals that has a last name.
 * It is uknown if Eevee( to relate Pokemon Yellow) or Squirtle was Gary's first Pokemon.
 * Gary in known to have fangirls and a fanclub in the anime.