Like Cheng-Huang, Guanti was a god based on a real man. According to the story, he was born poor and when he was a child he sold tofu for a living on the street (but historians say tofu was not actually invented until the Song Dynasty, hundreds of years later).
He was a famous general during the Han Dynasty (about 200 BC-200 AD). Artists always show Guanti as a red-faced man dressed in green. He was a war god, who also protected people from evil demons, and from anything that was unfair. He’s different from other war gods like the Greek god Ares because Guanti never starts wars. He only defends you when someone attacks you. He also could tell you the future.
Bibliography and further reading about Chinese gods:
The Gods and Goddesses of Ancient China, by Leonard Everett Fisher (2003). . One page for each god, with lots of pictures and some historical context.
Five Heavenly Emperors: Chinese Myths of Creation, by Song Nan Zhang (1994). Stories .
Chinese Mythology A to Z, by Jeremy Roberts (2004).
Dragons and Demons : Myths of China, by Stewart Ross (1998). A few Chinese stories, retold .
Dragons, Gods and Spirits from Chinese Mythology, by Tao Sanders (1983). More of a child’s encyclopedia.