Xue Rengui
The drama begins during a war between Tang and Goguryeo before Dae Jo-yeong is born. Dae Jung-sang, Dae Jo-yeong's father is introduced as a general. We are also introduced to Xue Rengui (Seol Ingui in Korean), a man with a brilliant mind who comes up with a plan to bring down Liaodong Fortress. After a failed attempt to assassinate the Tang emperor Li Shimin, Jungsang is captured by Tang. Seol, enraged for not receiving credit for his actions, frees him. Dae leaves Seol to himself, and heads to Ansi Fortress. Thereafter, Seol rescues some Tang soldiers about to be killed. He catches the emperor's eye and is promoted to the rank of general.