Which vassal state is Xihe clan?

In Zhao, Emperor Taiyi (Zhao Gao) came from Xihe family and took the goddess of the sun as his mother. Since the emperor, he has been an official in charge of divination. He has a prominent position and is proficient in divination and magic. More than 50 years ago, Zhao made a wrong decision, which led to Zhao's fiasco in the battle of Changping, and 400,000 people would be killed by Qin Jun. However, Zhao claimed that it was a divination mistake of Xihe nationality and blamed all the charges on Xihe nationality.