After I defeated the mysterious figure he turned to me and nodded as though he had been testing me. Is it possible that the mysterious figure will be an alli in a future game? And is it also possible that he can travel through time and is really from the future?[/font]

I doubt his " Time Travel " ability , He could be an ally , Depends what happens in the future games

so there's a new cutscene in final mix? he Nods? and yes, He was probably testing you and I say he does time travel.

Yup he is testing u but it's possible that he is a good guy but not sure because in kh1fm xemnas tested sora and Xemnas was a villian after all , anyway we will know later

Yeah, I just finally beat him myself as Terra, almost had a heart attack. Anywho, as the others said, we don't know yet. Hopefully something will be revealed in 3D or BBSv2