So I saw a picture of the 6th Apprentice, Luxu, and saw that his Black Coat zipper is triangular. The person who was speaking to Ira, the Unicornis Foreteller, was speaking to an individual who had the triangular zipper. This implies that Ira was not speaking to the Master of Masters, but Luxu, indicating that they meet sometime before Ava, the Vulpes Foreteller. catches up with him.

 

I'm still new to this site, so if anyone can pull the pictures from the trailer for comparison, and one from Luxu's page in the KH Wiki, I'd appreciate it.

 

That said, we just learned something new. Go wild, people. 

 

 

It is implied that Luxu is pretending to be the Master of Masters in front of the other foretellers, but when he' alone, he goes all Xehanort-ish: "This world is full of light".

Who knows. But as it stands, there is now a way to distincly tell them apart, in my opinion.