Gongsun Yuan
Although Gongsun Yuan was nominally a vassal of the Cao Wei state, he considered switching allegiance to Wei's rival state, Eastern Wu. Gongsun Yuan eventually yielded under pressure from the Wei emperor Cao Rui. He killed the Wu delegates but some of them fled to Goguryeo. The Wu emperor Sun Quan attempted to form an alliance with Goguryeo to launch a pincer attack on Gongsun Yuan, but Goguryeo eventually sided with Wei against Gongsun Yuan.