a Hinnagami is a kind of cursed construct found in Japanese folklore similar to a golem but possessed by a powerful yokai that bonds itself with whoever gave it life, appearing as a ghostly doll.
A Hinnagami is able to grant any and all wishes to its creator but at a terrible price, as the Hinnagami grows increasingly obsessive and demanding; eventually the inevitability of death occurs but the creator of a Hinnagami will find no peace as even in the afterlife they will find that a Hinnagami will follow them, for all eternity.