The Nansei Islands (Amami, Okinawa, and Sakishima)—with their climate, flora, and religious culture distinct from mainland Japan—fostered a system of gods and supernatural entities entirely separate from the mainland's concept of yokai. These include the Kenmun and Kijimuna, tree spirits residing in ancient banyan trees; Majimun, a general term for the demons permeating the islands; Ichijama, vengeful living wraiths; visiting deities like the Boze and Yokkabui, who arrive from the utopian realm of Nirai Kanai across the sea to dispel misfortune during festivals; and Kinmamon, a high-ranking deity possessing the high priestess, Kikoe-ōgimi. Each is inextricably linked to the uniquely Ryukyuan worldview of *seji* (spiritual power) and the sacred traditions of Yuta (shamans), Noro (priestesses), and Utaki (holy groves). Conveying the indigenous, pre-Buddhist faiths of the southern islands to the present day, these island deities and apparitions have captivated scholars of Okinawan studies since the prewar work of Fuyu Iha and Shinobu Orikuchi.