Goku is a 1,000 Man commander of the Chu Military.
He had a mustache and worn armor that was fitting for his rank.
At some point in his life, Goku joined the Chu military and managed to climb the ranks to reach that of 1000-Man Commander. Serving under Rin Bu Kun, Goku must have spent most of his life fighting across the Chu borders.
He thought he could defend against Roku O Mi's charge but was quickly slain.