|Family||Daisy, Professor Oak|
|Friends||Red, Leaf (Green)|
|First Appearance||Red and Green|
|Class:|| Gym Leader|
- "Yo! Finally got here, huh? I wasn't in the mood at Cinnabar, but now I'm ready to battle you. ... You're telling me you conquered all the Gyms in Johto? Heh! Johto's Gyms must be pretty pathetic then. Hey, don't worry about it. I'll know if you are good or not by battling you right now. Ready, Johto Champ?"
- — Blue in Gold, Silver and Crystal.
Blue Oak is the player's rival in the Generation I games and their remakes, and is a Pokémon Champion. During the Generation II games, Blue serves as the Gym Leader of Viridian City's Gym in the absence of Giovanni.
Blue is a young man with light skin, brown eyes, and light auburn spiky hair. In Red, Blue, and Yellow (Generation I), he wears a long purple shirt, dark gray pants, a necklace, and brown boots with black straps encircling them.
In FireRed and LeafGreen (Generation III), his appearance changes slightly; the colours of his shirt and pants are switched, so he wears a short-sleeved dark gray shirt and purple pants and black shoes. He also carries a light blue pack around his waist, and has purple bands around his wrists.
In HeartGold and SoulSilver (Generation IV), Blue appears older than he was in previous Generations. He is slightly taller and more mature-looking. He wears a black leather jacket, a black belt around his waist, khaki pants, and black shoes.
It is noted that Gary Oak, from the Anime, strongly resembles Blue.
In the Generation I games, Blue is a self-absorbed, rude, snarky and overly competitive rival to the player. He will often insult the player, and does not act as a good sport when the player defeats him in a battle. With each defeat, he insists that the player was lesser and weaker than he was, and denies the fact that he is not as skilled. He disrespectfully bids farewell, often saying, "Smell ya later!" as he walks away.
However, in HeartGold and SoulSilver (Generation IV ) Blue is a more mature, and much kinder person who gracefully accepts defeat when challenged at the Viridian Gym . As well a passionate and respectful guy that likes to battle a challenger no matter who they are in Generation V.
As previously noted, Blue serves as the player's Rival in the Generation I and Generation III remake games. In Gold, Silver, Crystal, HeartGold and SoulSilver (Generations II and IV), Blue has a less involved role, as the Viridian City Gym Leader.
Red, Green, Blue & YellowIn Red, Blue & Green, the player first meets him in Professor Oak's Lab, where he gives both a starter Pokémon. Professor Oak. As with every game, whichever Pokémon the player chooses, the rival (Blue) will choose the type that is effective against it (e.g. player chooses Bulbasaur (Grass), rival will then choose Charmander (Fire).
Later, after receiving the Pokédex, Blue will set out to find every Pokémon and be one step ahead of the player. As the player progresses through the game, he/she will encounter their rival in several locations and have to battle them every time.
Toward the end, after receiving all eight Gym Badges and defeating all of the Elite Four, it is revealed that Blue has already defeated the Elite Four and has become the Pokémon Champion. Challenging him, the player will battle Blue for the title, and when defeated, Professor Oak will come in and induct the player into the Hall of Fame.
Blue's appearance in the original games changes twice from the original appearance, throughout the game. The second appearance is similar to the first, with the addition of a backpack and a Poké Ball. The third (champion appearance), looks almost completely different, with an all new attire, and different hair.
In Yellow he is similar to that of the Red and Blue version. In this game however, his appearance is more similar to Gary's appearance from the anime series. Also, instead of choosing the opposite Pokémon, Blue chooses Eevee as it is the only one, while the player must take Pikachu. The first two battles with Blue are the deciding factor for what his Eevee will evolve into. It is decided on whether the player wins or loses the battles in Professor Oak's lab and on Route 22, or simply skips the latter area.
In these games, Blue's appearance also alters twice after a while, though not as dramatic as the champion appearance in the Red and Blue games. The battle sprite simply are in new poses each time. He is still the Champion until you defeat him.
Gold, Silver & Crystal
In Gold, Silver & Crystal, he is far less involved when compare to the previous. After the disappearance of Giovanni, the former Head of Team Rocket and Viridian Gym Leader, Blue takes over the Gym. Unfortunately for trainers, he is never usually at the Gym, making it hard to battle there. Unlike any other known Gym Leaders, Blue uses a variety of types in his Pokémon team.
FireRed & LeafGreen
In FireRed and LeafGreen, he has exactly the same as in Red and Blue. The only slight difference however is that his appearance does not change throughout the games.
HeartGold & SoulSilver
In HeartGold and SoulSilver, he is far less involved compared to FireRed and LeafGreen. Much similar to its namesakes Gold and Silver, Blue becomes the leader of the Viridian Gym. He still uses a variety of Pokémon. In these games, he is supposedly the strongest in Kanto.
Black 2 & White 2
- Main article: Blue (Adventures)
Blue has never officially been featured in the Pokémon anime series. He is however, the basis for the character Gary Oak. Gary's appearance, attitude, and relationships with other characters has been modeled after and is similar to Blue.
- Main article: Gary Oak
- Main article: Blue (anime)
|First Battle Sprite from Gen. I||
||Second Battle Sprite from Gen. I||
||Third Battle Sprite from Gen. I||
||First Battle Sprite from Y||
||Second Battle Sprite from Y||
||Third Battle Sprite from Y||
||Battle Sprite from Gen. II|
|Blue in the intro to FRLG||
||First Battle Sprite from Gen. III||
||Second Battle Sprite from Gen. III||
||Third Battle Sprite from Gen. III||
||Blue in the credits for FRLG||
||Battle Sprite from Gen. IV||
||VS Sprite from Gen. IV||
||Battle Sprite from Gen. V|
Red, Green and Blue
- Main article: Blue's Pokémon Teams (Red/Green/Blue)
- Main article: Blue's Pokémon Teams (Yellow)
Gold, Silver and Crystal
|Lv. 58||♂||Lv. 54||♂||Lv. 58||♂||Lv. 56||♂||Lv. 58||♂||Lv. 56||♂|
|Ability: Unknown||Ability: Unknown||Ability: Unknown||Ability: Unknown||Ability: Unknown||Ability: Unknown|
|Item: None||Item: None||Item: None||Item: None||Item: None||Item: None|
|Sunny Day||Recover||Roar||Fury Attack||Twister||Wing Attack|
|Leech Seed||Psychic||Swift||Sandstorm||Hydro Pump||Whirlwind|
|Egg Bomb||Reflect||Flamethrower||Rock Slide||Rain Dance||Quick Attack|
|Solar Beam||Disable||Extreme Speed||Earthquake||Hyper Beam||Mirror Move|
FireRed and LeafGreen
- Main article: Blue's Pokémon Teams (FireRed/LeafGreen)
HeartGold and SoulSilver
|Lv. 60||♂||Lv. 58||♂||Lv. 56||♂||Lv. 52||♂||Lv. 55||♂||Lv. 58||♂|
|Ability: Tangled Feet||Ability: Rock Head||Ability: No Guard||Ability: Intimidate||Ability: Chlorophyll||Ability: Intimidate|
|Item: None||Item: None||Item: None||Item: None||Item: None||Item: None|
|Whirlwind||Earthquake||Thunder Punch||Dragon Dance||Psychic||Roar|
|Mirror Move||Stone Edge||DynamicPunch||Return||Hypnosis||Dragon Pulse|
|Return||Megahorn||Earthquake||Ice Fang||Leaf Storm||Flare Blitz|
|Air Slash||Thunder Fang||Stone Edge||Waterfall||Trick Room||Extreme Speed|
Black 2 and White 2
- Champion League Tournament
- He has appeared in at least two of the main series games in every generation.
- He is the youngest Champion, the second is Iris.
- The main character of the game Golden Sun: Dark Dawn, Matthew, bears a resemblance to Blue.
- Blue doesn't always choose your weakness. In Yellow, he has to settle for an Eevee.
- He is the first Champion who ends up being a Gym Leader in later generation.
- In Pokémon X and Y, a lady sitting at the table in the Pokemon Center near Magneta Plaza in Lumiose City says that Blue has come to visit Kalos to study abroad a while back.
- It is unknown who was the Indigo League Champion before Blue. However, in the games, when Lance, the last member of the Elite Four, is defeated, he says that you WOULD have been the Champion.