On-Samun General served in the Goguryeo (Ancient Korean) Military almost his entire life. He was the right hand person of Supreme Commander Yeon Gaesomun. He was a martial arts expert. He took part in all 3 Tang-Goguryeo wars. After the death of Yeon Gaesomun he served under Geom Mojam. He helped build a stronghold for the people of Goguryeo in Han Fortress after the fall of Pyeongyangseong. On-Samun was one of the key figures in the korean military history. He was killes in Han Fortress after being betrayed by Prince Anseong and General Kims forces from shilla.