If you watch the KH 2 final mix secret ending, or the KH2 secret ending, the old man/ "bad guy" is wearing the same attire that Xehanort's heartless wore. Also, the picture of Xehanort in Ansems study, it is the same outfit. Not only what he wears that leads me to believe this, but his eyes are also the same yellowish-gold that Xehanorts are.
I was unable to find any pictures of said character, but I'm sure you know whom it is I am talking about.
I was unable to find any pictures of said character, but I'm sure you know whom it is I am talking about.