Kuroyama bloody mist.

The Kuroyama clan.

Long time ago the peaceful, warm and full of lights, Land of water also known as The Village Hidden in Mist was the most horrible village to exist. Every year hundreds of poor kids were killed and villages massacred. All the mist shinobis were trained into being assasins and were known for their soundless ambushes. In those times the village was called The Bloody mist. At the Shinobi exams, for you to show that you are the best, you had to kill your opponents, everyone. Remained alive only the gifted ones, the special ones, and the strongest ones.

The mist is also known for the unique jutsu's that are barely found anywhere else.  The Kuroyama clan, one that barely still exists, with two sole survivors, was gifted with the art of juinjutsu, which consists of forming contracts with ghosts and other powerful entities, and using their bodies in exchange for chakra.

The ritual was something you wouldn't wish even to enemies. A person from the clan, from a young age was taken to a weird creepy cage, where in the middle of it was a big rock, where the sacrifices were made. All around it was water and mist, so that you couldn't see the spirit entering. You couldn't choose. Either an entity chooses you and you live forever feeding it chakra, either no one chooses you and you get eaten as a sacrifice for disturbing the spirits.

The woman survivor was inerhited with a powerful really old ghost, that, as time flew didn't necesit as much chakra as the others. Whenever she needed to borrow its body she would summon either the whole body, which was only in case it was extremely needed, and which took a lot of chakra. In other cases she would borrow it's hand or other body parts that could help her. The body part was visible to her but completely invisible to others. The man survivor was inerhited with a powerful bear spirit that could enter and leave anyones bodies.

It was well known by the time the two people were adults that everyone with special jutsus and kekkei genkai's was considered a monster and were not welcomed anywhere.

They gave birth to a little girl and while constantly hiding, managed to train her and form a contract with a spirit. That day when they went out from the ritual people from the village near them were standing out with weapons and shouting to them to die. The two parents pushed their little girl hard away ordering her to run until she doesn't feel her legs anymore.