Ash's Pikachu (Japanese: サトシのピカチュウ Satoshi's Pikachu) is the signature Pokémon of the anime series, and the first Pokémon obtained by Ash on his journey as a Pokémon Trainer.
After Ash & the team gained Pikachu's loyalty in Littlefoot's Adventures of Wreck-it-Ralph, Pikachu became extremely loyal to Ash & Littlefoot and has maintained this loyalty, and while he is not always immediately trusting of strangers, he is generally friendly to humans, cats, dinosaurs and Pokémon alike. He acted as a guardian and big brother to Misty's Togepi, and has been seen mediating and even breaking up fights among other Pokémon, such as in Littlefoot's adventures of Pikachu's Vacation. In Littlefoot's adventures of Mewtwo Strikes Back, Pikachu, Meowth, and Meowth's clone were the only Pokémon not to participate in the giant battle; Pikachu stood motionless as his clone repeatedly slapped his face. Contrary to his distrusting nature, Pikachu took a liking to Misty very early in the series, and he has retained this liking of Misty throughout the series, such as when he was very happy to see her in The Scheme Team.