Unggoy Ultra

Unggoy Ultra is the the highest known Covenant rank.

Rank
The Grunt Ultra is the highest Unggoy rank seen so far in the Covenant military. Like Sangheili Ultras, Grunts Ultras wear distinct white/pearl-like armor.

Grunts Ultras can sometimes be seen commanding lower classes of Grunts in battle, even leading black-armored Special Operations Grunts into combat, and it is rare for the player encounter them when playing on lower difficulties, such as Easy or Normal.

Unlike Elites Ultras, Grunt Ultras do not appear to have any immunity with their command. It is just as likely that two or three will be encountered leading a small group of Grunts, yet the Elites, (or Brutes in the Loyalists) are ultimately in complete command; similar to the way that even minor Prophets outrank Sangheili Ship Masters, Grunt Ultras are inferior in rank to even Elite Minors.

These Grunts, like their lower-ranking cousins, appear in groups. They are very intelligent, making as few tactical errors as Major Domo Elites. They usually display even more bravery in combat than a SpecOps unit, and are more often used for specialized attacks, rather than generic millitary operations.

Combat
Grunt Ultras usually throw more grenades and are far more accurate and deadly at a greater distance than the lower ranked Major and Minor Grunts. They also wield Needlers with greater frequency than their inferiors, though it is still not uncommon for them to use Plasma Pistols. They can also take the same amount of damage Spec Ops Grunts do (more than three times as much as a Grunt Minor can), but they are still vulnerable to headshots (even though it may take more than one for lower-end weapons). Like SpecOps Grunts, they are rarely caught sleeping on duty. They still panic if they know that they are being overwhelmed, but are more likely to go berserk than panic - especially if one of their comrades was killed by a grenade. A Grunt Ultra, compared to an average Minor Grunt, can take much more damage and usually takes two to three melees instead of one to be killed, even on lower difficulties like Normal.

Background
The purpose of this rank designation has been generally unclear. They were first mentioned in Halo: First Strike, pushing carts of cleaning fluid, demonstrating that they still hold very low positions despite the title of "Ultra." However, they were also seen inside the Scarab walker in New Mombasa along with high-ranking Elites (Minor, Major, and Ultra). They were also seen throughout New Mombasa, Delta Halo and Cairo Station. This led some to believe that they were "technicians" or engineers (not to be confused with the Engineer species) of some sort, but the production book, The Art of Halo, confirms that they outrank Grunt Majors. It has, however, been suggested that white armor actually signifies manual labor, while the more silver armor signifies Ultra. Still, there is not a sufficient color difference to make this a significant case. It is likely that even though they are high-ranking Grunts, they are not free from manual tasks.

The rank is a rare achievement for an Unggoy, due to the fact that the species has a high death rate. Grunt Ultras most likely delegate a great degree of respect from the Grunts under their command, as their combat prowess must be exemplary - or they are just extremely lucky.

Appearances
These Grunts are seen in both Halo: First Strike and Halo 2. They are seen throughout Halo 2, but are far more frequent in the Heroic or Legendary difficulty levels than the Easy or Normal ones.

Halo: First Strike

 * Unyielding Hierophant- Two Grunt Ultras were seen pushing carts of cleaning fluid.

Halo 2

 * (Easy and Normal less common, Heroic and Legendary more commonly)- Seen throughout the level, most noticeable are in the hangars, but also in the Commons areas.
 * - Grunt Ultras attacked SPARTAN-117's position in the building near the Pelican crash site.
 * - A few Grunt Ultras were present on the Scarab command deck.
 * - A Grunt Ultra is dropped to help the Arbiter with some other Spec Ops forces at the exit of the Flood labs.
 * (Legendary only) - Grunt Ultras aid the Brutes at the beginning of the level.
 * - At the beginning of the level, and a few more times throughout the whole level, they are seen fighting the Flood.
 * - If you are lucky, the Grunt assisting you in the turret will be an Ultra. This is very rare, though. On Heroic and Legendary, two Grunt Ultras are present near this turret.

Trivia

 * Sometimes an Grunt Ultra's armor appears slightly darker, possibly meaning that they have more experience than standard Ultras.
 * If one plays Halo: Combat Evolved with an unsupported video card, but has at least 32 MB of video memory, all armor colors will be white, with some exceptions such as the Hunter - which has led to some fans thinking that all Grunts in Halo: Combat Evolved are Ultras. However, white is the basic color of all models in the Halo: Combat Evolved engine. The models are rendered with no specific color until selected by an algorithm that would determine which Grunt variant to spawn, determined by the difficulty level (meaning higher difficulties are more likely to spawn Grunt Majors). There is a degree of randomness involved, as the player may notice a Grunt Minor in one location, die, then realize it is now a Grunt Major..
 * More Grunt Ultras seem to have supported the Covenant Loyalists, as seen in the Halo 2 level High Charity.