Navajo Yeii Spirit, is a depiction of a irit considered by the Navajo to be a go-between between man and the creator. Yeiis control natural forces in and on the earth, such as day and night, rain, wind, sun, etc. A very special kind of yeii is the Yei'bi'chai, grandparent spirit or "talking God" who can speak with man, telling him how to live in harmony with all living things by following a few rules of behaviour and using only the basic things he needs to survive.