Wait... isn't she in the character sheets of kobold adventure?

Indeed she is! One of the game's only 'guest characters' if you will, though she doesn't really make any sort of appearance in the games. I was quite active in its Discord server for a while, and shared art and stories involving her there, she became quite popular. Almost a running joke at some points... and indeed, eventually the creator went and created a character sheet for her and a little story to go with it. I'm not really all that connected with the game or its developer anymore, so it's something of a neat little easter egg for those who know the character.

Yeah. That game just up and died. I doubt it will ever be finished.

Alas. Well, have no fear; Yastara lives on with me! ...as she has from the start, but still!

Is the version in that game different from the version here?

Possibly. I haven't really rigorously reviewed the story/sheet from KA and sussed out the discrepancies, but I imagine their idea of Yastara probably differs quite a bit from mine. If you have any specific questions, feel free to send a note!