A vocaloid song with and animated clip starring a starving she-wolf, a injured warrior and a demonic child

It's a clip I've seen long ago, it was in Japanese but I had seen a version with subtitles. I think it was Kagamine Rin or Ren. The art style was pretty nice, the colors involved a lot of black, red and white. The story went like this : An injured woman found shelter in a cave, but it was inhabited by a she-wolf. The wolf (who could talk) was about to eat her but agreed to listen to the woman's story first. Turned out this woman was a warrior who had killed a bunch of people, and was betrayed and stabbed right when she had decided to chill. The wolf was like "yeah, very interesting, but I'm still gonna eat you", but then the woman stabbed the wolf. And then she was killed by some kind of demon that came from inside of her. Anyone knows the title ?