Narhal was the captain of an Orion pirate ship along with his wife Susna. They were the first two Orions to be captured by the Federation, as a boarding party led by Captain James T. Kirk successfully prevented them from activating their self-destruct device.
Later, Narhal and Susna were broken out of the USS Enterprise brig when some of Armand St. John's "others" attempted to seize the vessel. Once this incident was resolved, they were returned to the brig and presumably transferred to Federation facilities on Gelb VII, as was the original destination of the Enterprise before their course was diverted to Pollux II (TOS comic: "All of Me")