Blue, a Pokémon Trainer and Professor Oak's grandson, arrives at the Kanto Pokémon League to challenge the Elite Four for the title of Champion. Displaying confidence, he declares himself an "incredible genius" after his Alakazam defeats Lorelei's Lapras using Psychic to lift and slam the opponent. Against Bruno, his Pidgeot overpowers Machamp with Wing Attack, prompting Blue to claim neither he nor his Pokémon have fought seriously yet. During his battle with Agatha, his Rhydon defeats her Arbok. Agatha provokes Blue by comparing him to his grandfather, causing him to angrily reject the comparison and assert that completing the Pokédex is merely a tool to gain strength; Agatha responds by sending out her Gengar from her cane's Poké Ball.

In the final battle against Lance, Blue's Blastoise trades attacks like Flamethrower and Hydro Pump with Lance's Dragonite. Though the outcome remains unseen, Blue ultimately defeats the Elite Four and becomes Champion. His reign is brief; he immediately awaits his first challenger, Red. Blue anticipates Red's arrival, expressing eagerness for their battle despite his new title.

Blue's Pokémon team during these battles includes Alakazam, Pidgeot, Rhydon, and Blastoise, demonstrating strategic use of type advantages and mobility. His interactions reveal a competitive demeanor and irritation at comparisons to Professor Oak, highlighting a strained familial relationship.