Forum:Notes 51 (Character Files info) - Ultima Spark

Square Enix e-shop listing, to show it's an official product. I'm assuming the info inside is as canon as the Ultimania.

Translations are scattered all over the the place. Compilation 1, compilation 2, Axel, Saïx, another translation of Saïx's story.

Some notable info:
 * Subject X is noted as having black hair.
 * Marluxia was apparently turned back into a Nobody (after initial defeat-reformation) and remade into a Xehanort vessel before he ever regained awareness.
 * Demyx may have met with the Master of Masters (or an associate) at some point; his location is said to be "unknown".
 * Saïx/Marluxia/Larxene stories all take place post-game.