Well, it was something else.
Aka a demon that doesn't understand human language, but tries to.
Saki a human that is in love and raised the demon-child Aka.
In the end Saki had a family in the village but he was not happy, so he decided to live his dying moments where he was with Aka. Then Aka after waiting for many years came to the old man give him a piece of his flesh making Saki an undead-human that lives longer than anyone...
Happy ending but weird in between
Akatsubaki