What Sora has along with his kind personality is a strong sense of justice. On top of Yen Sid telling him the org members are bad, he sees them wrecking havoc in other worlds constantly. Plus Demyx obviously has his bad side, too. He steals the talisman in Olympus Coliseum and you see how quickly he can snap into his serious mode aka “Silence, traitor.”
I’ve just recently started to replay KH2 (for about the billionth time), so I’m gonna throw in my two cents as well.
While soraspromise is right in that Sora does have a strong sense of justice and his actions being led by what Yen Sid was telling him and so on, I don’t think that’s all there is to it.
In KH2, I’ve noticed that Sora is very, very quick to jump to conclusions and be a little shit with sassy comments flying out on pretty much every world he goes to. This is pretty unlike him and something that’s not shown in another game besides KH2. And I don’t think it’s because of bad writing/forgetting Sora’s character.
I think it’s because of Roxas.
Before Sora wakes up, we get to see Roxas finding out about himself and being forced back into Sora.There are only a couple of pieces of dialogue that are really important here:
Roxas: “I hate you so much!”
DiZ: “You should share some of that hatred with Sora. He’s far too nice for his own good.”
A lot of people think that during this point Roxas did return to Sora willingly. But look at his face once he sees Sora, listen to his voice. Roxas isn’t willing, he’s tired, he’s resigned. He wants to fight back but goddammit nothing works. And no one seems to want him to be here, and the only one who did was taken away.
So he gives up. He joins with Sora. But not the way DiZ wanted him to~ Because Roxas didn’t join with him willingly, Roxas and Sora are disjointed. Roxas can’t very well take control of Sora’s body or anything. But he is very much there and definitely aware of his surroundings.
It’s why Sora cries when leaving Twilight Town. Why he’s friendly with Axel despite the fact that Axel kidnapped Kairi, and why he’s so ruthless against the Organization.
Because Roxas has his memories of the Organization back now—or at least the ones he can remember—and he felt like everyone there was keeping things from him about himself. He knows they were using him. He’s still angry about it.
And because he and Sora didn’t merge the way they were supposed to, his anger leaks into Sora.
Did you ever notice that after the battle with Roxas Sora’s suddenly a lot better about controlling his anger? The person Sora’s really most angry at is Saix—because he kidnapped Kairi and held her prisoner. And even then, it’s nowhere close to where he was the rest of the game.
It’s because Roxas finally understood. He got to talk with Sora. Figure out why he had to be the one. Once it clicks, he’s at peace. He finally lets it go and his heart relaxes. His emotions don’t leak into Sora again. Because he was willing. He let himself merge because he was now okay with it.
BLESS THIS POST AND BLESS KINGDOM HEARTS.
Little tidbits like that are everywhere; in the way Saix treats Axel, Xion and Roxas, in the way Ventus, Terra and Aqua interact with their surroundings, in Sora’s psychological state in Dream Drop Distance, in the entirety of Riku’s whole, freaking character arc… Kingdom Hearts is very much a fairytale, but not one working with archetypes, but with very layered, complex characters.
And it is to be admired for that beyond the Fandom’s giant faults, in my opinion.