An Lushan
An Lushan favored his son An Qing'en () (the son of his second wife, Lady Duan) and was considering appointing An Qing'en to be crown prince (instead of An Qingxu, who otherwise was in line to receive that title). Knowing that he was out of favor, and fearing that An Lushan was planning to kill him, An Qingxu, along with He, Yan, and Li Zhu'er, decided to assassinate An Lushan.