Don't even know how you made this sound so nice... But it's enjoyable regardless of how you made it.
Mystia's theme is probably my favorite for a second stage boss, simply because of how unique the melody is. Just hearing it loop over itself, somehow, feels smooth to listen to, even when it starts getting weird. I'm a little disappointed that this is mostly the original but in orchestral form, instead of something a little innovative/unique to do with the theme, raw Touhou is still great. Good work on this.