[It's an unusual name, and if it's another Master who's been imprisoned for twelve years... that wasn't so long after Sora remembers that she came to Destiny Islands. It can't be a coincidence. Just how is it they keep meeting these people who are connected to them anyway?]

No way...

[And then, when Riku's fists ball as he tells Sora about Mickey being forbidden to tell them, he can't help but feel that share that frustration. If Aqua had protected Riku and Mickey from the Heartless, then he owes his best friends' lives to her. They owe their world to her. And... why would Master Yen Sid think that it was okay to hide that from them both?]

How could Master Yen Sid keep that from us? We could have helped her, we were right there in the Realm of Darkness, if we'd known we could have gone looking for her! We could have-

[And then something really, really awful occurs to him. Worse than the guilt, worse than the knowledge that they'd been close enough to do something and never known that they could, comes the realisation that they have this knowledge now that she's trapped.

And if it's bad for them to know about it... ]

Riku... how are we going to tell Terra?