Fake Shimi was a pupil of Leilong, a member of the Anten Seven and the "real" Shimi. Assuming the identity of his mentor, he challenged Gene Starwind to a duel in The Seven Emerge.
The fake Shimi was a strong believer in a fair fight, making no attempt to ambush him whatsoever and instead issuing a challenge to him outright one day in advance.
Due to his limited screen time the exact level of his skill is difficult to determine. He was shown to be a competent gun fighter, enough to injure Gene, though he did still die in the end.