Jiralhanae Captain Ultra

The Captain Ultra is, according to Bungie.net, the highest rank a Brute can be. Some have confused the Ultra with the bodyguard (the bodyguards are the silver armored ones), and the Blue armored captains (weakest captain), because there armor looks very similar. In fact, There armor is a Teal color. They are rarely seen without Thunderstorm turned on, but are very deadly.

Also of note, is that the highest attainable Brute Captain rank as shown using the Thunderstorm skull is the gold armored Brute Captain Majors during Sierra 117 only.(Most likely because Ultras would make it too difficult.)