Pikachu:
S tier Who am I kidding? Limbo C/D
The electric mouse that spawned a thousand knock-offs has returned once again to waste a spot on your team!
Availability: Pikachu can be found in
Viridian Santalune forest and is listed as
uncommon rare, meaning it is the first electric type you can catch. If you were wondering, yes these Pikachu have a chance of holding the exclusive light ball which turns this rather week mouse into a nuke that can rival the power of mewtwo. However, because Pikachu is a pretty rare mon and the chances of it holding a light ball is only 5% (
7.5% 20% if you use compoundeyes) it can take hours to even find one holding a light ball. A thunderstone can be found easily on route 10 to evolve it into Raichu
Stats: Pikachu itself has decent speed, but awful defenses and attacking stats. However, if you acquire one holding a light ball, its attack and special attack double making it an extremely powerful offensive pokemon. Raichu has average bulk, good speed, and decent offenses
Movepool: Pikachu has access to thunderbolt and quick attack early. It receives an upgrade in electro ball at lvl 18. It receives the powerful thunderbolt pretty early in the late 20's. On the TM side, it can learn important coverage moves like dig and grass knot.
Typing: Pure electric type is pretty good defensively, only being hit super effectively by ground moves. Electric is a mediocre attacking type in-game, only hitting water and flying super effectively, but being resisted by grass and electric, and not hitting ground at all!
Important Battles:
I'm gonna assume you have a light ball, because that is really the only reason why you would consider Pikachu.
Viola: Pikachu can sweep this gym pretty easily, outspeeding both of her pokemon and hitting supereffectively with thundershock.
Grant: You can teach Pikachu rock smash and take out Amaura, but you likely won't OHKO tyrunt, and anything will OKHO you.
Korrina: Pikachu can't take more than one hit here, so it should probably only be used against Hawlucha mienfoo. Thunderbolt should OHKO both.
Ramos: I'd sit this one out. You might be able to defeat jumpluff but that is it.
Clemont: You should be able to sweep with thunderbolt and dig
Valerie: Dig deals with Mawile and Mr. Mime, but Sylveon will be a pain. Pikachu can't really take any hits if any here.
Olympia: Thunderbolt can deal with Sigilyph and Slowking, but might not OHKO so Pikachu might not make it past both. Meowstic could be a problem if pikachu isn't at full health.
Wulfric: You'll be OHKO'd by pretty much anything. Avalugg has poor special defense so a thunderbolt should take it out.
Team Flare: Pikachu is decent against team flare. It will take out the golbats and houndooms with thunderbolt and dig, respectively.
Malva: It's kind of a gamble here because pikachu might not outspeed pyroar and talonflame. You can OHKO both with dig and thunderbolt. Chandelure you should be able to ko with dig, but torkoal can take a hit. With Pikachu's terrible defenses, you'll most likely get OHKO'd by any attack here.
Wikstrom: Dig can take out klefki and probopass, but aegislash and scizor can take a dig and OHKO with practically anything.
Drasna: You can't really do much here than maybe take out Altaria. Noivern is gonna outspeed you and most likely OHKO.
Siebold: Everything else but starmie is an easy kill. Starmie may outspeed you and OHKO though.
Diantha: Pikachu can't really do much here but take out Hawlucha and even that is given, because it outspeeds you. Everything else either resists thunderbolt or has very high special defense. With pikachu's terrible defenses, it will likely be OHKO by anything.