Ash's Pikachu/Personality and characteristics

After Ash gained Pikachu's loyalty in Pokémon - I Choose You!, Pikachu became extremely loyal to Ash and has maintained this loyalty, and while he is not always immediately trusting of strangers, he is generally friendly to humans 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 Pikachu's Vacation. In Mewtwo Strikes Back, Pikachu,, 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 and Alola, Kanto!. It was revealed that Pikachu also loves drinking orange juice, most likely because of its sourness in The Fires Of A Red-Hot Reunion.

During the Hoenn saga, Pikachu temporarily developed amnesia and sided with for a while. On several occasions, Pikachu has developed an "electric flu" causing him to become overcharged and extremely powerful. During these instances, Pikachu will sometimes accidentally let off electric outbursts which can be set off on anyone, including Ash. In all of these cases, Pikachu did not mean harm upon anyone.

As shown in a handful of episodes, the first being Showdown at Dark City, Pikachu has a special fondness for ketchup, but he will eat and enjoy almost any other human or Pokémon food. A running joke in the anime also seems to be Pikachu using Thunderbolt at the beginning of each series to destroy a female companion's bike or shock the companion herself. This has happened to, , , , and.

Pikachu, like his Trainer, is always happy to battle. He often tries his very best, but when he loses, he doesn't complain or feel bad about himself, especially when Ash reassures him. Ash and Pikachu are almost identical personality-wise, and thus are the perfect match for one another. Most others agree, with the exception of Burgundy, who in A Connoisseur's Revenge! said that Ash had a terrible relationship with all of his Pokémon, though this is more due to her inexperience in determining such relationships.

In general, Pikachu as a species is not particularly powerful, but Ash's Pikachu is an anomaly, overcoming odds in numerous times. In Pokémon Emergency!, remarked that Pikachu's power "far exceeds its evolutionary level". In Showdown in Pewter City, he defeated Brock's Onix with an attack that triggered the sprinkler system causing Onix to be drenched in water, one of its weaknesses. Ash's Pikachu has also defeated very powerful Pokémon that Ash's other Pokémon were unable to, such as, and Mega. He was also the second of Ash's Pokémon to defeat a legendary Pokémon in battle, defeating Brandon's Regice to win the Brave Symbol. He later fought 's Latios to a draw in the semi-finals of the Lily of the Valley Conference. He has helped Ash win countless battles and Gym and matches.

The possibility of evolving into Raichu was first raised in the episode Electric Shock Showdown. After suffering a crushing defeat by Lt. Surge's Raichu, Nurse Joy presented Ash with a Thunder Stone. Ash allowed Pikachu to decide, but it smacked the stone away with his tail, choosing to become stronger as it is, and defeated Raichu using its superior speed. In the Sinnoh region, Pikachu battled a Raichu belonging to a trainer named Sho. The two were evenly matched, until Raichu used to secure victory, a move Pikachu could not learn. At a Pokémon Center, Ash revealed that he kept the Thunder Stone he acquired in Vermilion City in case Pikachu changed his mind about evolving. Once again, Pikachu chose not to evolve, and defeated Sho's Raichu in a rematch with a combination of speed and spinning techniques learned from. In the interim, stole the Thunder Stone, as they also liked Pikachu to stay as he is.

However, at times, has lived up to his species' frail and brittle strengths, particularly in Gym battles where he was defeated with relative ease by his opponent; for example, he was overpowered very easily by Lt. Surge's Raichu, Sabrina's Kadabra, Blaine's Magmar, Bugsy's, Whitney's Miltank, Chuck's , Roark's Rampardos, Fantina's Drifblim, Cress's , and Viola's , despite having a type advantage with Scyther, Poliwrath, Drifblim, Panpour, and Surskit. He also drew against Winona's and Norman's, and struggled against Crasher Wake's. Furthermore, he has lost twice to Trip's Serperior, as a Snivy in In the Shadow of Zekrom! and a Servine in A Rival Battle for Club Champ!, despite Trip being a starting Trainer and recently having obtained Serperior. In addition, Pikachu tends to struggle when his mobility is hindered, such as when the aforementioned Panpour weakened Volt Tackle with, or when his legs were numbed by Wulfric's and its , preventing him from using Quick Attack.

Pikachu became the second non-legendary Pokémon to defeat a legendary Pokémon in the anime after, beating 's in Pace - The Final Frontier!, giving Ash his final Frontier Symbol.

Pikachu is also the only one of Ash's Pokémon to accompany him to the Hoenn, Unova, Kalos, and Alola regions, and was intended to be the only Pokémon to accompany him to Sinnoh before was discovered to have stowed away on the ship Ash was taking. Up until the capture of Dawn's Pachirisu, Pikachu was the only Pokémon in the anime owned by a main character.

Pikachu is always becoming a constant target whenever he gets captured by Team Rocket. Sometimes, they succeed with nets, cages, capsules or different devices, but most of the time their plans always failed by Ash and his friends or something else. Whenever Pikachu gets released from their trap and reunites with Ash, he sends Team Rocket blasting off with his Electric attacks. Most of time in this case, his Thunderbolt. Sometimes, Pikachu sends them away even when he didn't get stolen. On other occasions, he battles them with Ash.

Even with his high level of electrical power, Pikachu has not stopped learning new attacks. Upon learning that Roxanne, the Rustboro Gym Leader used Rock types, Ash had Pikachu begin learning Iron Tail in All Things Bright and Beautifly!. After training hard, Pikachu finally perfected it in The Winner by a Nosepass, where he used it to defeat Roxanne's and earn Ash his first Hoenn Badge. In addition to giving Pikachu an advantage over Rock types, Iron Tail has allowed Pikachu to defeat many powerful opponents. In May's Egg-Cellent Adventure, during a battle with Team Rocket, Ash ordered Pikachu to do a Quick Attack. Much to the surprise of Ash and his friends, the Quick Attack morphed into Volt Tackle which sent Team Rocket blasting off. Until Dancing With the Ducklett Trio!, it has been one of Pikachu's signature moves, in which Pikachu replaced it with Electro Ball, which it learned while battling a trio of annoying. Not only that, Pikachu has used his Ability,, a few times in the anime. 