Pikachu is a bright yellow (electric type) rodent pokemon. Its height goes as tall as the knee of a young boy. Pikachu is Pokemon #25, and second main character within the Pokemon series. Pikachu is Ash's first Pokemon. Ash is the main character in the Pokemon series. The series begin with the scenes that you see in the Pokemon Blue game for Gameboy, then switches to a real battle of the Pokemon League on Ash's TV. Nidorino and Gengar are battling, while Gengar puts Nidorino to sleep, the trainer withdraws Nidorino and sends out an Onix.