Jiralhanae Captain Ultra

The Captain Ultra is the second highest attainable rank a Brute can achieve next to chieftain, and wear gold Power Armor, which signifies higher rank then the blue Brute Captain Majors.

Variations
Like most of the Covenant in Halo 3, units of the same rank bearing similar but different variations of armor, with different colors, underarmor, underarmor colors, etc. are a common occurence. As it has not been suggested by any source that these variations are different ranks, it is assumed that they are part of the same rank, but perhaps may signify other things such as behaviour, weaknesses, and strengths.