Sangheili Ultra

The Ultra Elite is a Covenant Sangheili (Elite) rank.

Rank

In comparison to the United Nations Space Command rank structure, the Ultras are believed to be the Covenant's colonel and captain analogs. They are just below the golden-armored Zealots in rank.

They command specific operations, unlike the Zealots, who command entire fleets and armies. Rtas 'Vadumee (a.k.a Half-Jaw) is another type of Ultra, Spec ops Commander, and his armor is plain white (which is a difference to other Ultra Elites, as their armor also has stripes of gray), and he's in command of the Spec ops forces.

It should also be noted that certain Honor Guards or Ultra Elites can be promoted to the high rank of Honor Guard Ultra.

Combat

Like their Zealot superiors, the Ultras are extremely skilled warriors. They also possess extra-strong energy shields that can withstand several times as much damage as those possessed by regular Elites, and they can take more physical damage as well. They often fight with heavy or dual-wielded weapons. Many also carry Energy Swords as their secondary weapon; when enemies get too close, or deplete their shield, Ultras let out a war cry, drop their currently wielded weapon, and pull the sword out for close combat. The 'Ultras' are able to continue in sustained heavy combat long after most Elite warriors' shields would have been depleted. They are particularly effective in close quarters combat, where their stronger energy shields and Energy Sword allow them take down large numbers of enemies.

Appearances

Several Ultra Elite corpses were seen in Halo: Combat Evolved - presumably killed in combat with the Flood - but they do not appear in battle until Halo 2. However, even in Halo 2, they are infrequent in number.

Yet, one of the main protagonists of Halo 2, Rtas 'Vadumee, better known as the "Special Operations Commander" or as "Half-Jaw", is an Ultra Elite. Rtas commands a force of Special Operations Elites that greatly assist the Arbiter in almost all of his battles on the Threshold Gas Mine and on Installation 05, although he only physically fights in three levels - Sacred Icon, Quarantine Zone, and The Great Journey.

Halo: Combat Evolved

Ultra Elite Corpses are seen throughout the campaign levels Two Betrayals, Keyes, and The Maw.

Halo 2

Ultra Elites appear more frequently on the higher difficulty levels; Heroic and Legendary, as fitting with their increased difficulty and the Ultra Elite's greater combat assets that the lower Major Domo Elite or the Minor Domo Elite.

Rtas 'Vadumee

The following is a list of areas that 'Vadumee appears in, on any of the four difficulties:

The Arbiter - Rtas 'Vadumme is the commander of the Special Operations force (Arbiter, Special Operations Elites, and Special Operations Grunts) that storms the Gas Mine, and coordinates the attack from the safety of a Phantom.
The Oracle - Rtas 'Vadumme joins in the attack, fighting the Heretics and the Flood. At one point, however, he and his men withdraw, leaving the Arbiter to fight off the enemies to kill the Heretic Leader. Then, 'Vadumme appears to exfiltrate the Arbiter from the Gas Mine in his Phantom.
Sacred Icon - Special Operations Elites once again under the command of Rtas 'Vadumee held a Covenant reinforcement point by way of Plasma Cannon, Energy Sword, and Plasma Rifle for the Arbiter to join them in the strike to retrieve the Sacred Icon from the Library. They held out long enough for a Phantom with further Special Operations Elites and several vehicles, including a Specter and two Ghosts.
Quarantine Zone - Special Operations Elites assisted the Arbiter in forging a path to the Library. About at the two-thirds mark, Rtas 'Vadumee sent a Phantom with another Specter and more Special Operations Elites to assist. When the Covenant force reached the gondolas, further Special Operations Elites defended the gondola from Flood attacks. When the gondola halted, Special Operations Elites awaited on the gondola to protect their sole exfiltration craft as the Arbiter retrieved the Sacred Icon. It is likely that the Brutes slaughtered the remaining commandoes that were defending the Gondola - one of the first acts of the Covenant Civil War.
The Great Journey - Rtas 'Vadumme drives a Wraith, escorting the Arbiter to the mouth of the Brute fortress before leaving the Arbiter, moving instead to retake a Brute-held CCS-class Battlecruiser in extreme low orbit. (E.L.O.)

Easy & Normal Difficulties

Metropolis - An Ultra Elite commands the Scarab battle walker that attacks New Mombasa. He dual-wields Plasma Rifles until sustaining a certain amount of damage, then charges with an Energy Sword with a roar.
Gravemind - Numerous Ultra Elites fight Brutes in the Mausoleum of the Arbiter on High Charity. They used higher ground on the edges of the circle-shaped room to rain fire with Fuel Rod Cannons on the Brutes. However, they also wielded Energy Swords, pummeling enemies that were too close for their heavy shoulder-mounted cannons. Two more were at the exit of the Mausoleum, escorting an Honor Guard Ultra.

Heroic & Legendary Difficulties

Cairo Station - An Ultra Elite, armed with an Energy Sword was in the rear vanguard of the Covenant force that deployed in Hangar A-02. A second, also armed with an Energy Sword, kills Master Sergeant Gunns in Armory A-01. On the easier difficulties, the Master Sergeant is killed by a Stealth Elite with a Plasma Rifle.
Outskirts - An Ultra Elite leads the attack on the Hotel Zanzibar in New Mombasa. He operates a Plasma Cannon until SPARTAN-117 approaches too close, then he will charge witn an Energy Sword.

Known Ultra Elites

Rtas 'Vadumee (Half-Jaw)

Trivia

Rtas is the only Ultra featured that does not have black/steel as his secondary armor color. This may hint that secondary colors play an important role in an elite's armor, much like modern day function badges play on military uniforms. Black may hint at infantry or ground combat positions while white, as in Rtas' case, may hint at spec ops. Or, it may simply imply that Rtas is a slightly higher/lower rank (as with the relation with Lieutenant Colonel and Colonel) or position (as with the relation with a Sergeant Major and a Command Sergeant Major) than a normal Ultra.
As of now, the only known caste of elites that the title "Ship Master" has ever gone to are Zealots. However, it is possible (and implied) that the title also goes to Ultras, whom probably command smaller ships such as light capital warships and maybe ships on the scale of CCS-class Battlecruisers.