I Like Anime

I’m trying to look for an anime I watched a while ago. I’ve been looking for a week but I can’t remember the name.

The anime was about this black haired guy who died and becomes a ghost. He formed a contract with a white haired guy who has some sort of spiritual powers. The white haired guy’s family was rich and in possession of some ancestral sword that did not have a sheath. I remember in one of the episodes the ghost guy made a sheath for the sword out of a sign. Also, there were flashbacks to the guys passed lives or ancestors.

The anime was only about ten episodes long. If any of you have an idea of what this anime is I’d appreciate if you could tell me the title. Thanks.