Vanitas

"You've done it, Ventus. Now that my body is about to perish, you and I will have to join together! The χ-blade will be forged!"

"Oh, grow up. Is that what you call friendship? You'll never know the truth unless you go out and look for it yourself. Come on, what could you possibly know when you're stuck here, looking at nothing but what's in your tiny world?"

"Because I am darkness. And I do stand by your side. I'm the shadow you cast. How much closer can I be?"

"Fine. Then I'll give you a reason to fight. Come and find me... at the one and only place to spawn the χ-blade, the Keyblade Graveyard. There, you're gonna see me choke the life out of Terra and Aqua. Then we'll see how long you play the pacifist."

“This may shock you, but we’re not the same like you think. I was just hidden deep inside of you, for a really long time. All Xehanort did... was tear me right out of you!”