Roku (A Yu Yu Hakusho story)

Roku Kurama, a fox and fire apparition of demon world, stalks the streets of Mushiyori City. Lives the life of a human as punishment for burning the village of her brother the "Legendary Bandit Youko Kurama."
In the human world, she found a way to use the spirit energy she had. As she developed, she started killing every other demon she came across.

Yu Yu Hakusho characters are not mine. This plot is; however, I realize that there are a lot of stories that occur after the events of this show.
Possible language warning for those who don't like bad language.