Blue Oak (オーキド・グリーン, Green Okido) is the rival of the player in the first generation games. After the incidents in the first generation Blue took over as the Gym Leader of the Viridian City Gym known officially as the Viridian Gym, as Giovanni had disbanded Team Rocket and gone into solo training. Blue does not specialize in a particular type of Pokémon and, like Giovanni before him, he gives the Earth Badge to Trainers who defeat him.
He's an unfriendly young man who usually utters the phrase "Smell ya later" once he's about to leave. Like Red, Blue's main goal is to become the greatest Pokémon master and he actually does manage to do this. Red doesn't hear about this until he beats the Elite Four. Once he does he battles Blue and wins, making Blue lose his title of Pokémon champion.
Three years after that, it's revealed that he has become the new Viridian City Gym leader after Giovanni fled the gym three years earlier. What makes him different from other Gym leaders is that he doesn't have a specific type of Pokémon.
Professor Oak is his grandfather and says that he doesn't know how to care for his Pokémon. This is probably inferred when he leaves Silph Co. while Team Rocket is overthrowing it, leaving Red to take them down.
Blue also appears alongside Red in Pokémon Sun and Moon, when the player reaches the Battle Tree.
- Gary Oak (Blue's counterpart in the anime and Electric Tale of Pikachu manga)
- Blue Oak (manga) (Blue's counterpart in the Pokémon Adventures manga.
|Pokémon Gym Leaders|
|Indigo League||Brock • Misty • Lt. Surge • Erika • Koga / Janine • Sabrina • Blaine • Giovanni / Blue|
|Johto League||Falkner • Bugsy • Whitney • Morty • Chuck • Jasmine • Pryce • Clair|
|Hoenn League||Roxanne • Brawly • Wattson • Flannery • Norman • Winona • Tate and Liza • Wallace / Juan|
|Sinnoh League||Roark • Gardenia • Maylene • Crasher Wake • Fantina • Byron • Candice • Volkner|
|Cilan/Chili/Cress • Lenora • Burgh • Elesa • Clay • Skyla • Brycen • Drayden / Iris|
Cheren • Roxie • Burgh • Elesa • Clay • Skyla • Drayden • Marlon
|Kalos League||Viola • Grant • Korrina • Ramos • Clemont • Valerie • Olympia • Wulfric|
|Galar League||Milo • Nessa • Kabu • Bea/Allister • Opal/Bede • Gordie/Melony • Piers/Marnie • Raihan|
|Pokémon Elite Four Trainers|
|Kanto Elite Four||Lorelei • Bruno • Agatha • Lance • Blue|
|Johto Elite Four||Will • Koga • Bruno • Karen • Lance|
|Hoenn Elite Four||Sidney • Phoebe • Glacia • Drake • Steven/Wallace|
|Sinnoh Elite Four||Aaron • Bertha • Flint • Lucian • Cynthia|
|Unova Elite Four||Shauntal • Marshal • Grimsley • Caitlin • Alder /Iris|
|Kalos Elite Four||Malva • Wikstrom • Siebold • Drasna • Diantha|
|Alola Elite Four||Hala • Olivia • Acerola • Kahili • Elio/Selene|