乞伏乾帰
In 400, Yao Xing sent his uncle Yao Shuode the Duke of Longxi to launch a major attack against Western Qin. Despite Western Qin's initial success in cutting of Yao Shuode's supply line, Yao Xing himself led a force to aid yao Shuode, defeating Western Qin's king Qifu Gangui in battle, nearly capturing Qifu Gangui's entire army and proceeding to take most of Western Qin's cities. Qifu Gangui himself surrendered to Southern Liang's king Tufa Lilugu, thus temporarily ending Western Qin's existence. In fall 400, believing that he was being suspected by Tufa Lilugu, Qifu Gangui fled from Southern Liang and surrendered to Later Qin. Yao Xing created him the Marquess of Guiyi and, in 401, took the unusual action of giving Qifu Gangui his army back and ordering him to defend his old capital Wanchuan (苑川, in modern Baiyin, Gansu), and while Qifu Gangui was in name a Later Qin general, he acted independently at times.