Before we get too deep into things, I'd like to put a quick note about his name. In EarthBound, his name is Pokey, while in Mother 2 and Mother 3 his name is Porky. This has been speculated to be due to either mistranslation or because Nintendo was afraid of copyright issues with Warner Bros. because of Porky Pig. In my opinion, I think it's the latter because I don't really think that the translators would've missed the obvious joke of naming the fat kid Porky (and his skinny brother Picky). Whatever the case, it has become clear that his official name is supposed to be Porky so that's how I'm going to refer to him.
In order to fully understand Porky, first we must look at his life before he became an insane villain. From what we can gather, it seems that the Minch's were very rich- at least until Ness's father allegedly borrowed a ton of money from them. The Minch parents do certainly dress like they're well off, and act like it to some extent. Porky and Picky on the other hand; well, they look more ragtag.
Porky is sporting one suspender and a pretty shabby haircut
But we can give them some slack for this, they are kids after all. Their parents don't really seem to love them very much either, and they also seem to physically harm them if they do something bad. Perhaps because of the way his parents treated him, Porky became the way he is. It is plausible, things like that do happen.
Yet we can't completely blame his parents, we also have to take into account other children. Porky's the kind of kid that would probably be a bully. The kind of kid who was picked on when he was younger, but now seeks to do the same to others. No one likes a bully, and no one likes Porky. He's an immature jerk.
And then there's Ness. The good kid. The kid that always hangs out with the kids that no one likes. Everyone's friend. Porky's only friend. Ness may not be particularly fond of Porky, but he is still nice to him. Ness is about as perfect as a thirteen year old can get, and Porky is jealous. He wants what Ness has; friends, a loving family, good looks, etc. Heck, he may even admire Ness. Because of this, he pushes Ness around a lot, and yet Ness is still there for him whenever he needs him. I don't think Porky is able to completely wrap his head around this, he can't understand why Ness still wants to hang around him, he can't comprehend his acts of kindness. Part of him wants to be Ness's friend, while the other wants to crush Ness; to see the ever-so-perfect boy be torn to bits.
On the same strange night that Ness chose his fate, Porky also chose his own, and these two boys were led down very, very different paths.
At some point, Porky was contacted by Giygas, and he was given a deal; if he helped Giygas, he would be able to see Ness crushed, just like part of him had always wanted. Porky seized the chance. Perhaps he did think it over, perhaps he did feel guilt, but he chose to become Ness's enemy. Unlike most of Giygas' human minions, Porky was acting of his own accord. Giygas never brainwashed him, he chose to do what he did because he wanted to.
Everytime you see him on your adventure in EarthBound, he's the same; a greedy arrogant jerkface that you'd like to punch. At least until you get to the final battle. At this point, he shows his true colors. His lust for violence and chaos has gone beyond beating up kids on the playground, it's come to destroying the entire Earth. If it means he has to die so be it, just as long as everyone who hated him suffers the same fate, even if it means destroying the one person who actually cared about him. When the battle's over, he leaves. The last trace of him we see is a short note addressed to Ness.
He then travels through time and space, gathering up groups of followers, and finally finds an impressionable place that he can take over. He's like an inter-dimensional Hitler. This place; the Nowhere Islands, is where he learns of a great power that can be used to destroy the Earth. Even though everyone now loves him, and he's reached a god-like status (both physically and in people's eyes) he still wants the world to get a taste of what they dished out to him so many years ago. It's not even the same people who were mean to him, it's their descendants. He claims he'll die of boredom otherwise.
Something strange also, he seems to hold the chosen four in a place of honor even though they opposed him. It seems as if he secretly admired them, and now that they're not around he can show it.
Unfortunately, he messes with the wrong family, and brings forth a new hero to oppose him.
I am going to make this a two-parter, so stay tuned for part two!
