From Bulbapedia, the community-driven Pokémon encyclopedia.
Ash's Pikachu (Japanese: サトシのピカチュウ Satoshi's Pikachu) was the first Pokémon obtained by Ash on his journey as a Pokémon trainer. Its universal voice actress is 大谷育江 Ikue Ohtani. However, in some episodes during the first season of the English dub, Rachael Lillis provided its voice when the original Japanese track couldn't be saved.
In the anime
In the first episode of the Pokémon anime, Pokémon, I Choose You!, Ash woke up late the day he was supposed to go to Professor Oak's laboratory to obtain his first Pokémon. When he arrived at the lab, the three available starter Pokémon, Bulbasaur, Charmander, and Squirtle had already been taken by other trainers who arrived earlier. Seeing that Ash was disappointed, Professor Oak gave him Pikachu, which did not take a liking to its new trainer. It refused to go into a Poké Ball, and when Ash failed to catch a wild Pokémon, it laughed at him. However, by the end of the episode, Ash gained Pikachu's trust by protecting it from an attack by a flock of Spearow and rushing it to the Pokémon Center. Pikachu and Ash soon became inseparable. In Pikachu's Goodbye, Ash gave Pikachu his consent to remain in a forest filled with Pikachu, but Pikachu returned to Ash's side.
In general, Pikachu as a species are not particularly powerful, but Ash's Pikachu is an anomaly, overcoming odds in battle numerous times. In Showdown in Pewter City, it defeated Brock's Onix with an Electric attack when Onix was drenched in water, despite Onix being naturally resistant to electricity. In Electric Shock Showdown, Pikachu fought Lt. Surge's Raichu and lost. During a resulting hospital stay, it refused to become Raichu's equal by evolving via a Thunderstone, and in the second battle, Pikachu overcame Raichu by using its superior speed. In Pokémon Emergency!, Meowth remarked that Pikachu's power "far exceeds its evolutionary level." Ash's Pikachu has also defeated very high level Pokémon that Ash's other Pokémon were unable to, such as Dragonite and Metagross. It has helped Ash win innumerable battles and Gym and League matches.
Pikachu is extremely loyal to Ash, and while it is not always immediately trusting of strangers, it is generally friendly to humans and Pokémon alike. It acted as a guardian and big sibling to Misty's Togepi, and it has been seen mediating and even breaking up fights among other Pokémon, such as in Pikachu's Vacation. In Mewtwo Strikes Back, it, Meowth, and Meowth's clone were the only Pokémon not to participate in the giant battle; it stood motionless as its clone repeatedly slapped its face.
Since its first encounter with Team Rocket in Pokémon Emergency!, Pikachu has been pursued by the trio of Jessie, James, and Meowth. Jessie, James and Meowth have gone through many attempts and devised many evil plans and came up with many scams at stealing this Pokémon from Ash and wanting to present it to their boss. Jessie, James and Meowth try, try, and try some more, but they just can't seem to accomplish the task!
As shown in a handful of episodes, the first being Showdown at Dark City, Pikachu has a special fondness for ketchup, but it will eat and enjoy almost any other human or Pokémon food. A running joke in the anime also seems to be the destruction of a female character's bike with one of Pikachu's Thunderbolts at the beginning of each series, which then causes her to follow Ash for the remainder of the series. This has happened to Misty, May, and Dawn so far.
Pikachu is the primary mascot of the Pokémon franchise, mostly due to Ash's ownership of it. It appears on nearly all merchandise and promotional material for the series, and became, due to the anime, the version mascot of and only starter Pokémon in Pokémon Yellow.
Pikachu became the second non-legendary to defeat a legendary Pokémon in the anime after Charizard, beating Brandon's Regice in Pace - The Final Frontier, giving Ash his final Frontier Symbol.
Pikachu was also the only Pokémon to come with Ash to Hoenn, and just the same one of only two Pokémon to join Ash on his journey to Sinnoh. It is worth noting that Ash tried to bring only Pikachu again but Aipom snuck on board the ship. Up until the capture of Dawn's Pachirisu, Pikachu was the only Template:Type2 Pokémon in the anime owned by a main character.
In Hoenn, Pikachu learned how to surf. It also learned how to box from Ash in The Punchy Pokémon.
In the games
Pikachu was one of Ash's three Pokémon in Pokémon Puzzle League. Red's Pikachu in Pokémon Yellow also seems to be based off of it.
In the manga
Pikachu has appeared in two mangas based on the anime, namely Ash & Pikachu and Electric Tale of Pikachu. In both, it was Ash's starter Pokémon, much like the first anime-episode.
- Pikachu is Ash's only Template:Type2 Pokémon and was the only Electric-type owned by a main character in the anime until the capture of Dawn's Pachirisu.
- Some of Pikachu's speech is consistent enough that it seems that some phrases actually mean something. For instance, Pikachu always uses "Pikapi" when referring to Ash (notice that it sounds somewhat similar to "Satoshi"). Other speech includes:
- For DP013, Professor Oak's lecture is about Ash's Pikachu. He writes this Pokémon senryū about it: パートナー サトシとピカチュウ いいかんじ Partners Satoshi and Pikachu: a pleasant feeling.
- Because there is no indent on Pikachu's tail, many cite this as proof that it is indeed male. Some also site a crush that Dawn's Buneary, who appears to be female, has on Pikachu as proof. However, because all Pikachu prior to Generation IV lacked an indented tail, this is not concrete proof. Additionally, the gender of Dawn's Buneary is not confirmed.
- Out of all five regions that Ash visited, Kanto and Hoenn are the only ones that Ash started out with just Pikachu. He did try to go to Sinnoh with Pikachu alone but Aipom followed him. At the beginning of each, Pikachu was also, in some way, injured, and ended up destroying the bike of a girl who would later travel with Ash.
- Through out the series the yellowish color of Pikachu has become lighter and Pikachu's body has become narrower (presumeably from weight loss).
For more information on this Pokémon's species, see Pikachu.