Ash's Pikachu
Template:Pokémon from the anime Pikachu is Ash Ketchum's Starter Pokémon. He obtained it from Professor Oak in Pallet Town. Although Pikachu didn't obey him at first, after a series of events, it became his best friend and has appeared alongside him in almost every regular episode since the first one, including all of the movies. He is voiced globally by Ikue Ōtani (大谷育江 Ōtani Ikue).
History
Before Meeting Ash
In Template:EP, it is shown that when he was a Pichu, he used to be a solitary Pokémon who didn't know how to use his electric shocks in battle. At one point, the strong odor emitted by a trio of Koffing made him fall off a cliff. However, he was saved by a Kangaskhan, who decided to take him into his pouch as if he were its other child. Pichu developed for weeks in the Kangaskhan family, but began to feel ill when he saw that he was a great burden to the Kangaskhan that took him in. While everyone was asleep, Pichu leaves the cave that served as the Kangaskhan's home and mourns through tears. In the middle of a lonely night, he begins to shout "Pika!" and immediately evolves into Pikachu, causing great excitement in the Pokémon, which sets off on its new journey.
In The Beginning Series
In Kanto
Pikachu is given to Ash in the first episode of the anime, Template:EP, by Professor Oak after arriving late and after the three Starter Pokémons had already been chosen by other trainers. Pikachu initially dislikes its new trainer, mocking him for not having Pokémon trainer abilities and frequently electrocuting him. But after Ash sacrificed himself to save him from a flock of Spearow that began attacking them, Pikachu understood the true affection his trainer had for him and launched himself at the Spearows to defeat them with a powerful Thundershock.
Team Rocket has been after Pikachu since they first saw him in Template:EP after seeing how powerful he was for destroying the Pokémon Center with his electric powers.
In Template:EP, Pikachu has his first Gym Battle against Brock, where he battles Brock's Onix, but is easily defeated. Pikachu later recharges his electricity and in the rematch, easily defeats Brock's Brock's Geodude with a single move, and Brock brings out Onix again. Pikachu is about to defeat Onix thanks to the water from the fire sprinklers, but Ash stops him.
In Template:EP, he has a battle against Lieutenant Surge's Raichu where he is completely outmatched, leaving him seriously injured at the Pokémon Center. There, Nurse Joy gives Ash a Thunder Stone so that Pikachu can evolve into Raichu and thus defeat Lieutenant Surge, but Pikachu refuses to do so. Pikachu has his rematch the next day against Raichu, this time emerging victorious by using his superior speed to his advantage and allowing Ash to win the Thunder Badge.
In Template:EP, Ash uses it in his battle against Sabrina for the Swamp Badge. He faces off against her Abra, which appears to be asleep even before it leaves its Poké Ball. Abra does nothing, and Pikachu is somewhat intimidated. However, when Pikachu attacks it with Thundershock, Abra wakes up and uses Teleport, at which point it evolves into Kadabra. Ash orders Pikachu to use Thunderbolt to fill the entire field and render Kadabra's Teleport attack useless. Pikachu carries out Ash's orders. Kadabra uses Confusion to deflect the attack and send it back to Pikachu, causing severe damage. Kadabra uses Psychic to control Pikachu's body, forcing it to get up and dance. Kadabra throws Pikachu several times against the ceiling and then the ground, repeating this attack several times until Ash decides to give up, thus Kadabra defeats Pikachu and Sabrina wins the battle. In Template:EP, in the rematch against Sabrina, Ash had planned to use Haunter in the battle, but Haunter escapes, so Ash decides to run away before fighting, but Sabrina turns Misty and Brock into dolls. Ash comes back to fight, but Haunter escapes again, so Pikachu had to face Kadabra again. Pikachu tried to hurt Kadabra, but Kadabra's psychic attacks were much stronger than Pikachu's. When Pikachu was about to lose again, Haunter appears and starts playing pranks, making Sabrina and Kadabra laugh. Ash and Pikachu won the badge thanks to Haunter.
In Template:EP, Ash was about to release Pikachu to live with a pack of wild Pikachu, seeing how happy he was with them. However, Pikachu returns to Ash, refusing to leave his side.
In Template:EP, Ash uses Pikachu in his battle against Blaine for the Volcano Badge. He battles his Rhydon, which he manages to defeat, but loses to the Magmar's Flare.
In Template:EP, it faces Otoshi's Marowak, which it manages to defeat with Thundershock, despite the fact that Electric-type attacks do not damage Ground-type Pokémon.
In Template:EP, it faces Pete Pebbleman in the preliminary stages of the Indigo Plateau Pokémon League, which, thanks to its evasion and Ash's strategies, is no match for Pikachu, as it even falls weakened.
In Template:EP, it faces Jeanette's Bellsprout. Pikachu is unable to perform any effective attacks, as Bellsprout resisted the electric attacks due to its roots in the ground, and then Pikachu is hit and defeated.
In Template:EP, after dodging Team Rocket and facing them multiple times, he arrives exhausted at the round of 16 to face Richie and his Butterfree, but despite everything, he manages to weaken him and resist the fight until he is confronted by his Charmander and is defeated.
In the Orange Archipelago
Pikachu accompanies Ash on his journey through the Orange Archipelago.
In Template:EP, he battles Rudy's Electabuzz, however, he is defeated by Rudy's Thunder Punch, with Rudy winning the first round.
In Template:EP, he faces Tad's Polywrath, where despite having a type advantage, he is defeated by Tad's Water Gun after being put to sleep with Hypnosis.
In Template:EP, Ash uses it in the Double Battle against Luana for the Jade Star Badge where it battles alongside Ash's Charizard against Alakazam and Luana's Marowak. At first, Charizard refused to cooperate with its partner, believing that it could handle the battle alone, but eventually Charizard ends up working with Pikachu after the latter saves it from being hit hard by its opponents, and the two manage to defeat them by working together.
In Template:EP, in the Orange League, Pikachu faces off against Drake's Ditto, which leaves Pikachu in a difficult situation. However, because Pikachu was in better physical condition than Ditto, it was able to withstand the attack better and defeats Ditto with its electric tail, although the fight exhausted Pikachu.
In Episode 114, he brings out Pikachu to battle again, this time against Drake's Dragonite, where a close-range Thunderbolt attack gives Ash victory in this Orange League, making this the first of two official Pokémon Leagues they have won to date, along with the Alola League.
In Episode 118, he battles Gary's Umbreon, however, he is defeated by Gary's Eevee. At the end of the episode, Ash decides to take Pikachu back to Johto with him.
In the Gold & Silver series
Pikachu is very helpful to Ash during his travels in Johto, as it is used in all of his Gym battles, helping him win several of them.
In the episode Template:EP, it is used in the Malva City Gym battle, in which it battles Hoothoot and Dodrio, defeating both. However, it falls to Pidgeot.
In Template:EP, it is used in the Azalea Town Pokémon Gym battle against the leader Bugsy/Antón and his Metapod. It manages to defeat him, but loses to the Rage Slash of his Scyther.
In the episode Template:EP, it faces Whitney/Blanca and her Miltank in the Wheatfield Town Gym, which had previously defeated Ash's Cyndaquil and Ash's Totodile, and the same thing happens to Pikachu. In the next episode, Ash uses the same Pokémon again in the rematch against the leader, devising a plan this time: Cyndaquil tires out Miltank, Totodile makes holes in the ground to knock it off balance, allowing Pikachu to defeat Miltank and earning Ash the Plain Badge.
In Ghost to Ghost, Ash uses it in his battle against Morty for the Fog Badge, facing off against Morty's Gastly, where it is easily defeated by its Darkness.
Ash uses it in his battle against Chuck/Hannibal in episode Template:EP, where he faces off against Poliwrath, where despite having a type advantage, he is defeated by Double Slap.
In Template:EP, he along with Ash, Misty, and Brock, trying to save a baby Lugia and then reunite it with its father.
In Template:EP, Professor Namba chooses Sparky and Ash's Pikachu as test subjects for the device the duo previously used on their Pokémon. Before Professor Namba could test it, Oliver came in and rescued Ash, Richie, and the gang. However, Professor Namba triggered the alarm which summoned Butch and Cassidy. The duo had a rematch with Sparky and Pikachu using their Hitmontop and Houndour respectively. Both Pikachus aimed their Beam at the machine that powered up the Pokémon, destroying it. Both Hitmontop and Houndour were rendered useless without the machine and were eliminated by Sparky and Pikachu. After Team Rocket was defeated, Sparky faced off against Professor Namba's Electabuzz with problems with that. However, Sparky destroyed the machine Professor Namba was using, and Ash's Pikachu defeated Electabuzz.
In episode Template:EP, Pikachu battles Jasmine's Magnemite, which he manages to defeat, but the battle exhausts Pikachu. He then battles Jasmine's Steelix, where, tired from the previous battle and also having a typing disadvantage, he is quickly defeated by Jasmine's Iron Tail.
Pikachu is also used in the battle against Pryce's Piloswine in Ash vs. Pryce!, when it seemed like Piloswine was going to win, but the leader gives up to teach Ash that sometimes a trainer must retreat for the sake of their Pokémon.
Pikachu faces Clair's Gyarados and Clair's Dragonite in Eight and Last. Pikachu manages to defeat the former, but falls to the latter's Hyper Beam.
In Template:EP Pikachu battles against Jackson/Vincent's Azumarill in the Silver Conference/Silver Congress quarterfinals. After a tough battle, it manages to defeat it, but is defeated by its Magneton when it is hit by its Triattack after being Paralyzed with its Thunder Wave.
In Template:EP Ash uses Pikachu against Harrison where it faces off against his Kecleon, which Pikachu manages to defeat with great difficulty, however, it is quickly defeated by its Metal Claw of its Sneasel.
In Template:EP, Ash and Pikachu head to the Hoenn region on a boat, but Pikachu is trapped by a Team Rocket magnet, causing him to suffer a severe electric fever.