Koga

"Fwahahaha! A mere child like you dares to challenge me? The very idea make me shiver with mirth! Very well, I shall show you true terror as a ninja master. Poison brings steady doom. Sleep renders foes helpless. Despair to the creeping horror of -type POKéMON!"

- Koga, Pokémon FireRed and LeafGreen.

Koga served as the Gym Leader at the Fuchsia City Gym. Two years later, during the Generation II games, Koga also became a member of the Elite Four and his daughter, Janine took over his gym and used Type Pokémon as well.

He specializes in Poison-type Pokémon, and as a Gym Leader gave out the Soul Badge for trainers that could defeat him.

Red, Green, Blue & Yellow
Koga first appears in the games as the Fuchsia City Gym Leader. His gym was constructed with an array of invisible walls, fashioned into a maze. This forces the player to walk through the maze fighting Gym members, with the destination in the middle where Koga awaits.

Gold, Silver & Crystal
Later, in the Generation II games, Koga has been promoted to Elite Four status. With the absence of a Gym Leader at Fuchsia Gym, Koga leaves the Gym under his daughter's care, Janine, making her the new Gym Leader.

FireRed & LeafGreen
In the remakes of the original games, Pokémon FireRed and LeafGreen, Koga is once again a Gym Leader, as it takes place during the same time period. The only difference is the level of his Weezing, and his updated appearance.

Anime
After the appearance of Koga and a small incident with Team Rocket, Koga and Ash finally have their battle. The two have a one-on-one battle, with Ash using his Charmander, and Koga using his Golbat. Initially having some trouble, Charmander was unable to hit the Golbat, but after using Fire Spin, Ash was the victor. Upon leaving Koga rewarded Ash with the Soul Badge.

HeartGold and SoulSilver
First Battle=

Rematch=

Stadium
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Round 2=

Stadium 2
Round 1=

Round 2=

Voice actors

 * English: Stan Hart
 * Japanese: Hōchū Ōtsuka
 * Polish: Radosław Popłonikowski
 * Spanish: Juan Fernandez
 * Iberian Spanish: Gerardo Vasquez

Trivia
In a Pokémon card related to Koga, called Koga's Ninja Trick, there is a symbol that looks similar to a swastika. However, it is actually totally different, in positioning and in meaning. A Swastika is in a diamond angle, and the points on it point clockwise; the symbol depicted on the card was in a square angle, and the points were counter clockwise. The symbol on the card was of a different culture and was many years before the Nazi Party, and meant "peace". When the card was released in the U.S., it was changed to a different symbol.