Beastly beauty

Miyuki Akuma (originally Kurohime Akuma) was trained to be one thing her whole life; an assassin. When her mother dies trying to protect Akuma when she was three her father becomes cold and declares that Akuma will be trained to become nothing more than a wepon.

There's just a tiny detail he didn't count on. She wasn't actually his child. Akuma's mother escaped from her original world in order to protect her child from the evils that stole Akuma's mother's family from her. She left after terribly dark and 'evil' demons was sealed away into her baby. Akuma's mother made sure that the man she chose to take her dead husband's place would think that Akuma was his.

And now after nine years of what Akuma could only describe as hell her demons take her back to the world where she belongs- the world of naruto.