Blue Oak (オーキド・グリーン Green Okido in Japanese) is the primary rival of Red and the grandson of Professor Oak. His Japanese name is Green, because Pokémon Red and Green versions were the original releases in Japan.
His anime counterpart is Gary Oak.
Blue Oak is the rival to the player in the original Pokémon Red and Blue games for the Game Boy. He also appears in the remakes of Red and Blue, FireRed & LeafGreen that appeared on the Game Boy Advance, and makes smaller appearances in Gold and Silver for the Game Boy Color, and HeartGold & SoulSilver for the Nintendo DS.
Blue is the grandson of Professor Oak, who sets out at the same time as Red in the first generation games and their remakes. Like Red, he is a trainer from Pallet Town. At the beginning of the game, Blue will select the starter Pokémon that is most effective against the starter Pokémon the player chose. As the player progress through the game, the player will encounter Blue many times and often battle him. At the end of the game, after the defeat of the Elite Four, the player will be informed that Blue has already been proclaimed Pokémon Champion. The player will immediately proceed to battle Blue, as there can only be one trainer crowned as the Pokémon Champion.
In the second generation games, the player finds that Blue is has become the Gym Leader of Viridian Gym, replacing Giovanni. However, he often leaves the city and is rarely found in his gym, which causes problems for trainers wishing to challenge him.
In Pokemon Black 2 & White 2, Blue takes part in the Pokémon World Tournament and can be fought in the Champions Tournament, with Giovanni taking his place in the Kanto Leaders Tournament.
Blue often comes across as a smug and arrogant character and has little respect for Red. At the end of battles he often appears stuck-up in victory or ungracious in defeat and usually bids farewell with the phrase "smell ya later". Even Professor Oak himself says that Red cares for his Pokemon better than Blue does.
Blue Oak's first appearance is in the Pokémon Adventures first chapter, VS. Mew. He appears for the second time in the third chapter Vs Kangaskhan trying to capture the titular Kangaskhan.
In Pokemon Gold & Silver & Crystal
- Pidgeot Lv. 56
- Alakazam Lv. 56
- Rhydon Lv. 54
- Gyarados Lv. 58
- Exeggutor Lv. 58
- Arcanine Lv. 58
In Pokemon HeartGold & SoulSilver
- Pidgeot Lv. 60
- Rhydon Lv. 58
- Machamp Lv. 56
- Gyarados Lv. 52
- Exeggutor Lv. 55
- Arcanine Lv. 58
- Pidgeot Lv. 72
- Rhyperior Lv. 70
- Machamp Lv. 69
- Tyranitar Lv. 70
- Exeggutor Lv. 67
- Arcanine Lv. 68
In Pokémon Black 2 and White 2
- Aerodactyl Lv.50
- Exeggutor Lv.50
- Gyarados Lv.50
- Alakazam Lv.50
- Arcanine Lv.50
- Machamp Lv.50
- Blue Oak is the only character in a Pokemon game who is both the player's rival and the Pokemon Champion.
- He is the only Pokemon Champion in a Pokemon game not to induct the player into the Hall of Fame.
- He is one of the two NPCs in the Pokemon games which have been both gym leaders and Pokemon Champions. The other being Wallace.
- He is notable for being the only gym leader in all the Pokemon games not to center on a specific type of Pokemon.
- He is also one of 3 Pokemon Champions not to have a specific type theme, sharing this with Cynthia and Alder.