Wu Sangui
Wu Sangui was caught between the Manchus and Li Zicheng's forces. He requested Dorgon's help in ousting the rebels and restoring the Ming Empire. When Dorgon asked Wu Sangui to work for the Qing Empire instead, Wu had little choice but to accept. Aided by Wu Sangui's elite soldiers, who fought the rebel army for hours before Dorgon finally chose to intervene with his cavalry, the Qing army won a decisive victory against Li Zicheng at the Battle of Shanhai Pass on 27 May. Li Zicheng and his defeated troops looted Beijing for several days until they left the capital on 4 June with all the wealth they could carry.