Shipmaster
From Halopedia, the Halo wiki
Rank
A Ship Master is a Covenant title for a high ranking Covenant member who is in command of a ship. This rank is equivalent to the UNSC naval "Captain". Ship Masters command Starships within the Covenant, but they still fall under the command of their fleet's Supreme Commander. It is one of the Zealot ranks, all golden armor, they are the Field Masters, Ship Masters, and Fleet Masters of the Covenant alien juggernaut. An example of this is Orna 'Fulsamee, who was the Ship Master of the Truth and Reconciliation.