The only thing I think makes sense is Onaga. Why? Because they have storyboards for Onaga's ending. They have a storyboard for every character's ending in the Krypt, including Onaga. He's the only character thusfar that I 100% believe is an SU.

This is old. So far it's only proven that you can play these characters only by using a modded Xbox. While some people dont mid this...i think most peopel want a legit unlockable that can be taken online.