Takes place before Part 1 - Chapter 2...
A Corridor of Darkness opened up within a hidden cavern just below the Castle of the Two Sisters, the person stepping out of it was none other than the Keyblade Master of Darkness, Xehanort.
"Hmm...what have we here?" he asked no one in particular as he gazed at the crystalline tree, which was slowly losing its glow, "This is without a doubt the artifact that prevented my arrival..." he opened his right palm and hovered it in front of the tree, "let us fix that, shall we?"
Darkness flowed from his fingertips into the tree, causing its glow to die out instantly. Just then, black, thorny vines sprouted from the ground, snaring the tree and strangling it. They went after Xehanort as well, but with a wave of his hand, he countered with a vast aura of darkness, making the vines back away, fearful of his power.
"Hmph. I don't recall coming here to become plant fertilizer." he stated as he exited the cave and entered a ravine. He turned around and looked up at the Castle of the Two Sisters, decrepit and in near ruins. He sneered, "Oh...I do believe I am getting some where now."