New evidence suggests that Ash was not Pikachu’s first — I knew there was a reason that Pikachu was such a jerk at the beginning!
Ok, so bare with me here — a bold statement I know — but after a fair bit of research and a lot of work done by Reddit user Oufour, it is becoming increasingly clear that Ash was not Pikachu’s first ever trainer. To explain, we'd best start at the beginning (how else would you start), by this I mean, the first encounter.
Ash shows up late and is unable to choose a Pokémon , seeing how sad Ash becomes, Professor Oak offers him Pikachu instead. A great deal you might think — yeah, if Pikachu weren’t such a menace. Pikachu fights Ash at every possible opportunity and Ash is totally unable to control the yellow ball of mischief.
Now, this isn’t completely out of the ordinary — Pokémon can be disobedient and can stop listening to their trainers — but this is only the case when they outgrow one another, usually around level 20. This is never the case at the very beginning, as it was with Pikachu. So, this is strange — what reasons can we assume?
Did you get a look at Pikachu’s Pockeball compared to everyone else’s? It has a Lightning bolt on it — nothing like this exists in the series and all other Pokémon pokeballs are unadorned. The theory that follows here is that it is, in fact, a seal.
Seals are are used as accessories that alter the way in which a pokeball will open. The lightning bolt, for example, adds a lightening effect to the opening animation. These seals were available only in the fourth game in the series, Pokémon Diamond and Pearl, and are unusable in other variations. From this then we can deduce that Pikachu is likely to hail from Sinnoh, not Kanto.
The assumption that Pikachu comes from Sinnoh and not Kanto boils down to the trainers.
Training a Pokémon is a full-time job, one that needs experience and skill. To get a Pikachu with the correct balance of skills in the wild is almost impossible, a trainer would be needed. Trainers were not present on Kanto at the time of the Kanto games. In these particular games, there was no actual breeding mechanic, hence making it highly probable that breeders weren't around at the time. This leaves us with the fact that Pikachu is most likely to have come from Sinnoh.
Sinnoh? How can a Pokémon from Sinnoh end up with Professor Oaks and then in Ash's hands? The answer is pretty simple: power. The professor is often found working on very important projects, and with the potential of power outages interfering with his research, Pikachu ownership seems to make perfect sense. This is proven in episode 2, where we see a Pikachu-powered generator in the professor’s lab.
Now, if we look at Pikachu himself, we see that he is a grumpy, disobedient little rascal that wants nothing to do with Ash — but why is he such a dick?
The reasons here are simple: First off ,he is a Pikachu, not a Pichus — he is at his stage-two evolutionary level. No, I am not saying he is a teenager and it can be expected, I am saying that this means he would have had to have been nurtured extremely affectionately for this to occur.
Pikachu’s evolve through happiness (and physical activity, battle included) and Pikachu misses his breeder (Pikachu believes this to be a trainer). To level up the Pikachu he would have been loved, walked, and played with for months on end — he could even have been given a special pokeball. Incidentally, the breeder may have allowed Pikachu to remain outside of the ball most of the time — this also shows us why Pikachu is so averse to getting in his ball. Then out of the blue, he is packed into a crate and he never sees the breeder again — I think he has every right to be hacked off.
Piakchu wasn’t obstructive and disobedient on purpose, he was just being loyal to the breeder; as far as he is concerned he already has a trainer. Or on the flip side of that, he had a trainer that abandoned him and now finds it hard to trust trainers.
When Ash saves Pikachu from the sparrow hoard, Pikachu regains that trust in his newly acquired companion and almost immediately becomes devoted to his new trainer. It also may suggest another reason Pikachu is so averse to the ball: it reminds him of his previous trainer — the one who abandoned him.