Gary Oak

Gary Oak is the grandson of Professor Oak and the rival of Ash Ketchum and Ashley in the series whose starter Pokémon was a Eevee that later evolved into a Umbreon.

Personality
The day Gary started out on his Pokémon journey, he came off as an arrogant and an egotistical Trainer, much like Blue (Gary's game counterpart). His chosen starter Pokémon was Eevee and he even had a group of cheerleaders who cheered him on in all of his battles and they would go so far as crying whenever he lost. He didn't walk on his journeys like most Trainers did; instead he had his own sporty red convertible with a chauffeur. Gary loved when he got a chance to make fun of Ash and Ashley by bragging about how far behind Ash and Ashley were compared to him. He also gave Ash the pet-name of "Ashy-boy" (Japanese: "Satoshi-kun"), which occasionally seems to annoy him. His style of training at that point was to capture many Pokémon and to use the strongest, as a stark contrast to Ash and Ashley, who were more focused on developing a bond with their Pokémon.

His arrogance continued overtime during Ash and Ashley’s journey in Kanto until he challenged the Viridian City Gym Leader, Giovanni, to a Pokémon battle for his final (but not necessary) Badge in The Battle of the Badge where his team was brutally defeated by Mewtwo. However, this still didn't change his arrogance. It would take a loss at the Pokémon League way later on against Ash for Gary to finally realize that he greatly needed to change himself.

In his few appearances during the Johto saga, Gary seemed to have become the complete opposite of who he was. He became much more polite and respectful to others, including Ash and Ashley.

Anime
Gary is Ash Ketchum's rival who first appeared in Pokemon - I Choose You!, where he left Pallet Town and wanted to become a Pokémon Master before Ash did. In the beginning, Gary claimed to be the best of the best and had the typical smug attitude, known by having fangirls and a fanclub to go along, but, as the anime moved forward, he became less prideful and arrogant than that of his earlier appearances in the anime.

In later seasons, while Gary still retains his somewhat arrogant attitude, he's a much kinder and friendlier person who is considerably more polite and respectful to other trainers.

On Hand

 * Umbreon
 * Blastoise
 * Dracozolt
 * Dracovish
 * Arctozolt
 * Arctovish

With Professor Oak

 * Krabby
 * Aerodactyl
 * Arcanine
 * Nidoking
 * Dodrio
 * Fearow
 * Kingdra
 * Magmar
 * Skarmory
 * Scizor
 * Alakazam
 * Golem
 * Pinsir
 * Houndoom

Kanto League

 * 1) Boulder Badge
 * 2) Cascade Badge
 * 3) Rainbow Badge
 * 4) 7 unidentified badges

Johto League

 * 1) 10 unknown badges

Hoenn League

 * 1) 8 unknown badges

Sinnoh League

 * 1) 8 unknown badges

Unova League

 * 1) 8 unknown badges

Kalos League

 * 1) 8 unknown badges

Pokémon League Status

 * Indigo Plateau Conference (Indigo League) Loses to Ash: Runner-Up
 * Silver Conference (Johto League) Loses to Ashley: Top 16
 * Ever Grande Conference (Hoenn League) Loses to
 * Lily of the Valley Conference (Sinnoh League) Loses to
 * Vertress Conference (Unova League) Loses to
 * Lumiose Conference (Kalos League) Loses to
 * Manalo Conference (Alola League) Loses to

Contests
Extreme Pokémon: Runner-Up

Achievements

 * Honor of Kalos medal