Gary and Ash grew up as best friends since they were neighbors in Pallet Town but that all changed once they got older when they discovered their different views about Pokemon, Ash viewed them as friends that should be treated with love while Gary viewed them as monsters that should be trained for battle. Once they both turned ten years old and got their first Pokemon's they became rivals and had a competition to see who can become the greatest Pokemon trainer first. In the anime as Ash is about to head into a forest he reads a sign that says "Gary was here! Ash is a loser!" for proof of the rivalry. Gary is a very arrogant boy who even has his own cheerleaders to support him while Ash is a boy who dreams of being the best like no one ever was and believes in right morals.
His knowledge of Pokemon comes from his grandpa, Professor Oak, therefore Gary knows more than Ash and is always a few steps ahead of him.In the beginning of the series Gary is a smart-aleck trainer however, as he matures once time passes his personality begins to mellow. He eventually grows into a nice and humble person. Throughout the Kanto and Johto League his rivalry with Ash is like oil and water. This changes after his crushing defeat at the Indigo Plateau Pokémon League, his attitude towards Ash, who finished in the top 16 far ahead of his rival, changes.
Gary starts to become mature with his Pokemon as he starts to treat them right with proper care once he travels alone wanting to better re-establish himself as a trainer. His rivalry with Ash comes to an end at the Johto League when Ash defeats Gary. After his loss, he then decided to no longer compete for the same goal as Ash, but he dedicate his career into Pokémon research. To end the rivalry Gary gives Ash half of his broken Pokeball and Gary has the other half. He continues to motivate Ash on ways of bettering himself as a trainer. Gary is what urges Ash to start yet another new journey by traveling to the different regions across the world, such as Johto, Hoenn, and Sinnoh.
Despite his many absences in the series, Gary continues to remain a character, and one of Ash's most valued friends. He later appears in an episode of Diamond and Pearl series helping to preserve a group of highly endangered Shieldon with Professor Rowan and his team.
4 Sheildons (temporary)
- Gary is Ash's only rival with a last name.
- Has fangirls and a fanclub in the anime version.