Kaidan, or "ghost," is a term used in Japanese folklore to describe the spirits of the deceased. These spirits are often believed to linger in the physical world due to unresolved issues or unfinished business. Kaidan can take various forms, from vengeful spirits seeking retribution to benevolent ones offering guidance. In traditional stories, Kaidan often appear during specific times, such as the Obon festival, when families honor their ancestors. They are commonly featured in Japanese literature and film, where their tales explore themes of life, death, and the supernatural, reflecting cultural beliefs about the afterlife.