They are two of the “Four Heavenly Emperors”. “Tian-Huang Da-Di” is the one directing the North and South Poles, the sky, the earth, the people. He is also in charge of the stars and the wars.
“Tu-Huang Di Zhi” is the Heavenly Emperor (Female) responsible for the bearing, breeding and growing of all living things. She is also responsible for land and mountains on earth.