khthonian
Khthonian is an English adjective derived from the Greek khthonios, meaning "earthly" or "of the earth," and by extension "of the underworld." In classical Greek religion and later scholarship, khthonian (often rendered chthonic in English) is used to describe deities, powers, and rites associated with the earth and the subterranean realm rather than with the sky or Olympus.
Etymology and scope: The term comes from khthon, "earth" or "soil." It emphasizes the primal, subterranean aspect
In myth and cult: Khthonian deities and powers include Hades and Persephone, who preside over the underworld
Modern usage: Today the term is mainly encountered in classical studies, archaeology, and the study of religion,