Oliver is a Pokémon Trainer from Goldenrod City in Johto who challenged
Ash Ketchum to a Pokémon World Championships ranking battle while in Vermilion City. They had a 1-on-1 battle and he was defeated by
Ash's Pikachu. As a result of the battle,
Ash Ketchum ranking increased to 1,512.
His Japanese name Seiya is named after his voice actor Seiya (Seiya Ishikawa 石川晟也) of the Japanese comedy duo
Shimofuri Myojo. Seiya's hometown in the anime is Kogane City which is based off of the real work city Osaka and that is voice actor Seiya's hometown.