Pokémon: Battle Frontier is the ninth season of Pokémon and the fourth and final season of Pokémon the Series: Ruby and Sapphire, known in Japan as Pocket Monsters: Advanced Generation . It originally aired in Japan from October 6, 2005, to September 14, 2006, on TV Tokyo, and in the United States from September 9, 2006, to March 3, 2007, on Cartoon Network.

Ash Ketchum, known as Satoshi (サトシ) in Japan, is a character in the Pokémon franchise owned by Nintendo, Game Freak, and Creatures. He was the protagonist of the Pokémon anime for the first 25 seasons, as well as the protagonist of several manga series. In Japanese, the character is voiced by Rica Matsumoto. In the English dub, he was voiced by Veronica Taylor in the first eight seasons and Sarah Natochenny afterwards. Ash is a young man who travels with various companions, aiming to fulfill his dream to become a Pokémon Master; his Pokémon lineup constantly changes over the course of the series, with its sole constant member being Pikachu, Ash's first Pokémon. Ash is loosely based on Red, the player character from the Generation I games Pokémon Red and Blue. Satoshi Tajiri, the creator of Pokémon, has stated that Ash represents the 'human aspect' of the series, and that Ash reflects what he himself was like as a child.