I knew it had to be either Ashura or Yasha/Ashura...I went through the music looking for "that song from the flashback scene", since it's so pretty. Moebius as well - that played during a lot during the Yasha/Ashura scenes at the Moon Castle, so I thought it might be their relationship theme, but I seem to have gotten things mixed up. I also wanted to find "Fireseeker", since I remembered it from Syaoran and Kurogane's fight. I like it when there's slow music during fight scenes, for some reason.