Demon Slayer: Blade of Mist

[Original direction + OC characters and CP + growth direction + original ghost] Two hundred years ago, his ancestor became an evil spirit and became an eternal shame for the family. Two hundred years later, he stepped into the Demon Slayer Squad with a sword, just to cut off the head of his ancestor with his own hands. A ronin travels wildly across the country, killing ghosts alone with his family's swordsmanship. After a night of deadly battle in a mountain village, he is discovered by Yoshiyuki Tomioka, a water column, and is led to Mount Samagiri for training. Taking the family's Huayantian as his bones and the breath of water as his veins, he practiced hard for a year and forged his own "breath of mist". People kill ghosts to protect them. And he kills ghosts in order to put an end to them. ——The immortal who has lived for two hundred years must be terminated by his own hands.