at the keyblade graveyard, Xehanort is close to create the X-blade, he just needs one more heart, That one ends up being Kairi's, and he kills her, forging the X-blade. Then Sora, Riku and Mickey try to attack him, but failing in the attempt

Xehanort: "At last... The X-blade is forged..."

Sora: "Why...? WHY HER!?!?"

then, the other guardians came, but it was too late, the X-blade is already forged

Donald & Goofy: "Sora!"

Ventus: "That... That damn sword..."

Aqua: "Thought we'd never see it again..."

Roxas: "I guess seeing it means trouble..."