Hiroki is a Pokémon Trainer that battled against
Ash's Rockruff and
Ash Ketchum at the Pokémon School. He lost the battle after
Ash's Rockruff used the Z-Move Ultra Dash Attack.
Hiroki is based off of Hiroki Kobari (古張裕起) who's stage name is
Abareru-kun, one of the hosts of
Pokénchi. He revealed on
Pokénchi #75 that this character Hiroki was based off of him.