Do you need a character sheet for her? Thanks to this being more story oriented, I could more make up what would be cool on the fly (of course running it by you before it happens) and form her character and abilities over time based on how the battle goes. It wouldn't be just random abilities, but things I see would be fit. As we know she would be holding back so it would make sense why she wouldn't introduce everything at the start, or even have the chance to use it at all if she dies unexpectedly before she would reveal something.