In many mythologies, chthonic deities are responsible for overseeing the underworld and the earth's depths. These deities govern aspects related to death, the afterlife, and the fertility of the land. They often mediate the relationship between the living and the dead, ensuring a balance between these realms. Examples include Hades in Greek mythology and Yama in Hindu belief. Their roles are crucial in explaining the natural cycles of life and death, as well as agricultural fertility.