Complex sentence: He played the Metron in the "Arena" episode in Season 1 where Kirk fought the Lizard-man and was also the head man on a planet of pacifists who would not trade dilithium crystals in "Mirror Mirror".
Split into simpler sentences: He played the Metron in the "Arena" episode in Season 1 where Kirk fought the Lizard-man. He was the head man on a planet of pacifists who would not trade dilithium crystals, in "Mirror Mirror".