Castle Oblivion lived up the name it was given for the purposes of yourself, IV, V, XI, XII. Given that reports I know of the fiasco there, I am sure you are aware of at least half of those demises. Since that time, the Keyblade Master has awoken again, leading to the unfortunate but perhaps inevitable demise of Xaldin and IX. And as I've told you, both VIII and XIII have turned traitor.

[Which leaves him with only Saix, Xigbar, and Luxord. Because he's not mentioning Xion. She faded from everyone else's memories, and he considers this to be a test of Zexion's]