天乙
According to legend, Yi was a slave of a man named Youshen (). When Youshen's daughter married Tang of Shang, he became Tang's slave. He was gifted in cooking, so Tang made him his chef. While he served Tang his meals, he used this opportunity to analyse the current issues of the time, such as the bad points of Jie of Xia. He also proposed his plan to overthrow Jie of Xia. He earned Tang's trust, became Tang's right-hand man and was made 'Yin'.