Hakuoki - the Sorrow of Ghosts

(I read a lot of Hakuoki fics written by other people, but I didn't like the ending very much, so I made it myself.) He is a powerful ghost clan. She is a modern young spy, but now she is the only descendant of the Oni no Yuen family. What she experienced was beyond his imagination. She lives in the Shinsengumi warehouse, living a human life, silently mourning in a corner where no one knows.