Roxas
1. Black is... slimming? I don't see it. Orgy robes are bulky, ugly things.
2. JuuUMP~ You jump in KH games. Everywhere. It's faster and funner than walking.
3. Two games are about me!- KHII and KH Days.
4. Well, not really. They keep stealing the show after the prologue. KHII is obvious. KH Days, while Roxas is the main character, has both Axel and Xion as real scene-stealers.
5. On the other hand, those proglogues were huge. KHII's legendary 3 hour+ prologue. This was the first obvious hint not based on misdirection or referencing a game that, uh, me and Niu have played.
Further hints, if they were required, would have involved dialogue samples. Roxas dialogue samples not being the least bit subtle.