Gary Oak, known as Gary Carvalho in Brazilian Portuguese adaptations, hails from Pallet Town in Kanto. He is Professor Oak's grandson and a childhood acquaintance of Ash Ketchum. Starting his Pokémon journey, he chose Squirtle as his starter, coinciding with Ash's initial desire for that species. Gary displayed fierce competitiveness and arrogance early on, frequently boasting of his superiority over Ash and his collection of Gym Badges. He traveled in a sporty red convertible with a chauffeur and cheerleaders who supported his battles. His training emphasized capturing numerous Pokémon and deploying the strongest in battle, contrasting Ash's bond-focused approach. He often provoked Ash with the nickname "Ashy-boy." Gary collected at least ten Kanto Badges, including the Boulder, Cascade, and Rainbow Badges, plus additional unspecified ones, and secured at least eight Johto Badges. Multiple defeats prompted a shift in his attitude. A loss to Melissa in the Indigo Plateau Conference Top 32 sparked introspection. This transformation continued after reaching the Top 16 in the Johto League Silver Conference. Following a full battle loss to Ash there, Gary acknowledged defeat graciously, presented Ash with half a broken Poké Ball as a symbolic gesture, ended their rivalry, and renewed their friendship, marking his transition away from training. He then pursued a career as a Pokémon Researcher, mirroring his grandfather's profession. His research centered on Pokémon habitats and conservation, leading to collaborations like one with Professor Rowan in Sinnoh. At Mount Coronet, he protected Shieldon from poacher Pokémon Hunter J. Using knowledge of local ecosystems, such as a Beedrill nest location, he orchestrated escapes to safeguard the Shieldon. He cooperated with Ash and friends during this event, strategically deploying his Blastoise, Electivire, and Umbreon to minimize risk to the Shieldon while countering threats. His approach to Pokémon care, initially overshadowed by competitiveness, included gestures like kissing Poké Balls before releasing his Pokémon, revealing underlying concern. He displayed anxiety when his Arcanine and Nidoking were psychically attacked by Mewtwo. As a researcher, he continued to influence Ash's journey, offering motivation and occasional assistance. He joined the demanding "Project Mew." Within this project, he developed a dynamic with Ash's friend Goh, frequently provoking him with critical remarks about his abilities, intending to test and potentially stimulate Goh's growth as a Trainer. His Japanese voice actor interpreted this behavior as Gary recognizing Goh's potential and deliberately inciting reactions similar to Ash's earlier responses. His Pokémon team featured his starter Blastoise, alongside frequent use of Arcanine, Umbreon, Electivire, and Dodrio. He employed a rotation system, adjusting his team based on battle needs. After transitioning to research, he primarily retained Blastoise and Electivire but occasionally enlisted other Pokémon for specific tasks.