- “We fight one another now, but we should be fighting the true enemy. Humans.”— Jul 'Mdama greeting Kaidon Panom
Jul 'Mdama is a Sangheili and was the Lord of Bekan Keep in the rural state of 'Mdama, where he lived with his wife, Raia 'Mdama, and his children, two of which are Dural and Asum. He later became the leader of the Covenant Remnant, assuming the title of the Didact's Hand.
The Civil War
Jul served as a Shipmaster within the Covenant, though it is unknown whether he fought during the Great Schism. After the war, Jul returned to his keep in 'Mdama, still uneasy about the outcome of both the war with humanity and the San 'Shyuum. Jul spent much of his time in debate over how Sanghelios should be run now that the war was over, while his wife, Raia, was more concerned how the Sangheili race would rebuild in agriculture and engineering. When Kaidon Levu 'Mdama decided to side with the Arbiter Thel 'Vadam and his quest to pursue a cease-fire with humanity, Jul was torn between agreeing with Levu or attempting to assassinate Thel 'Vadam. In the end, he decided to side with Avu Med 'Telcam, leader of a religious sect known as the Servants of the Abiding Truth which believed Thel 'Vadam to be a traitor and a heretic due to his actions, and his proposed resolution to the growing problems. Jul and his friend, Forze 'Mdama, traveled to the state of Ontom to stage a coup d'etat and plan the Arbiter's assassination alongside 'Telcam and his armed forces. He managed to get several Sangheili shipmasters to agree to his terms and steal the Unflinching Resolve from the Aanrar Shipyard. They proceeded to hide the warship in a quarry five kilometers from Bekan Keep until it could be used.
While agreeing with 'Telcam's views on the Arbiter, he began to grow suspicious of the source of munitions and weapons 'Telcam was receiving to strengthen the Servants. During one of 'Telcam's supply runs, Jul followed him to New Llanelli to observe 'Telcam meeting with one of his suppliers, which turned out to be Kilo-Five, led by Captain Serin Osman. Jul, shocked that 'Telcam was dealing with humans, tried to escape but was captured and almost killed by Naomi-010. Jul was taken prisoner by Kilo-Five and brought aboard the UNSC Port Stanley, where he was interrogated. He was later transported to ONI Research Facility Trevelyan to be studied by ONI scientists.
During Jul's time on ONIRF Trevelyan, he was kept prisoner in the newly erected camp on the Shield World and subjected to some degree of interrogation by ONI scientists. Jul was eventually allowed to wander the Shield World but only when accompanied by Prone To Drift and whilst wearing a rigged explosive vest similar to one that Huragok were forced to wear by the Covenant.
Whilst held prisoner on the Shield World, Jul was fed genetically engineered food developed by ONI that could potentially be used as a biological weapon against the Sangheili. This food caused Jul to suffer from nausea, and vomiting.
Through mimicking his human captors, Jul would eventually glean information from Prone To Drift about the location of the Ur-Didact, as well as information detailing a system of portals from the Shield World to other Forerunner artifacts across the galaxy. Even though Jul was told of the danger of using these portals, he still viewed them as his best possible chance of escaping ONI clutches. Using the Huragok's instincts to protect Forerunner technology, Jul was able to force Prone To Drift into removing his explosive vest then jumped into the active portal.
Jul appeared on the Sangheili colony world of Hesduros, where he meets Panom and several youngsters. It turns out that these colonists have lost contact with the Covenant about a year prior, and have no knowledge of the Great Schism or the end of the war. Jul asks the locals to help him contact his keep. When he does, Jul learns that Raia and Forze were both killed by the Arbiter's forces while fleeing Sanghelios after the failed assault on Vadam Keep, despite Kilo-Five's attempt to defend their vessel (under the guise of a Kig-Yar privateer).
This news crushed Jul's soul and he asked to be left alone for a while. One of the youngsters approached Jul as he was admiring the Forerunner relics on the planet and explains to him the Forerunner symbols that were encrypted on Jul's belt. They show Jul a second holy gate where he finds the same symbols that were on his belt; the symbols for the Didact and coordinates to Requiem. Panom and the others, religious as they are, believe that the Forerunners sent Jul to Hesduros to find the Didact and bring him back to them. They agree to help Jul with whatever ships they can spare and to avenge his wife.
- “Shipmaster 'Mdama...It is where you said it would be.”— Storm Elite
- “No, my loyal friend. The planet is where the Forerunners promised us it would be. Find us a way inside. Requiem's treasures shall be ours.”— Jul 'Mdama
Four years later in 2557, the Covenant Remnant were still attempting to gain access to the Shield World Requiem when the UNSC Forward Unto Dawn drifted into the planet's orbit. In an attempt to prevent any humans who might be on the ship from gaining access to the planet, Jul ordered his troops to board the ship and eliminate the threat. Roused from thousands of years of dormancy, Requiem reacted to the presence of a Reclaimer, John-117, aboard the Dawn. As Requiem scanned the Dawn, Cortana awakened John-117 in response. Eliminating several Covenant boarding parties, John-117 manually fired a Hyperion missile from the Dawn's hull, destroying one of Jul's ships. Scanning John-117, Requiem opened a massive portal in its metallic shell to the planet within, trapping all nearby Covenant ships along with the Dawn within a powerful gravity well.
Continuing his quest to commune with the Ur-Didact, Jul's ships performed Slipspace jumps directly into the planet's hollow centre and advanced toward the core, despite meeting fierce resistance from Requiem's native inhabitants, the Prometheans. Meanwhile, the UNSC Infinity picked up Cortana's distress beacon aboard the UNSC Forward Unto Dawn and attempted to follow its signal into the gravity well.
After escaping Requiem, the Didact traveled to Installation 03 and, under his control, the Covenant Remnant immediately attacked the UNSC science facility, Ivanoff Station,and searched for the Composer. That is when Jul witnesses the composer's power and the true power of the Forerunners; the Didact fires the composer at Ivanoff Station, digitizing and, presumably, killing every human.
The Didact and the Covenant jump to Earth where they fire the Composer aiming directly at the city of New Phoenix. Jul's vengeance is almost finished as the entire human race will slowly be exterminated by the Composer.
Unfortunately, the moment did not last for Jul 'Mdama. John-117 followed the Didact to Earth, and with the help of the Infinity and Cortana herself, he defeats the Didact, destroys the Composer, and forces Jul to retreat.
- “I know what the Librarian will say, Glassman. She will tell us where all things sacred are hidden in this galaxy. Ships, weapons, bounties beyond our imagining. And she will tell us how to make those miracles... our own.”— Jul 'Mdama addressing his troops
In 2558, the Covenant Remnant continued searching for new secrets that may still be locked within Requiem. Infinity engaged the Covenant Remnant as soon as they jumped out of slipspace and immediately deployed Spartan Fireteams to clear out hostiles on the planets surface in order to allow science teams to move in and continue with research. The Spartan-IVs cleared out many Covenant Remnant archaeological sites; Jul 'Mdama tried in vain to stop the humans from foiling his plans but the Spartan-IV's proved themselves more than capable.
During this process, Spartan Crimson Team gathered intel on Covenant archaeological teams, discovering that Jul had found a Forerunner artifact. With the aid of Promethean Knights, Jul attempted to stop the humans from retrieving the artifact, but the Spartans were able to escape along with it.
The Spartans took it back to Infinity where scientist Henry Glassman was sucked in just after he attempted to experiment with the artifact. Glassman was teleported to a Forerunner construct on Requiem's surface, where the Covenant Remnant retrieved him. Jul ordered his troops to invade one of the UNSC Science Bases, Copernicus, which is where those who were stationed there worked on finding The Librarian that John-117 encountered six months prior.
Jul sent Glassman to this particular location for him to figure out how to activate the shrine which housed The Librarian in exchange for his life. Apparently, Jul wanted to learn the locations of powerful weapons that might be hidden in the galaxy from her after awakening her.
However, before they were killed, scientists from Copernicus managed to inform the Infinity that they had sighted Jul 'Mdama. Spartan Fireteams Crimson and Majestic were dispatched to locations where Jul 'Mdama was rallying his forces in order to cripple them. Jul 'Mdama was sighted at almost every location but managed to teleport from one place to the other in order to escape the Spartans. Crimson followed 'Mdama through all the portals, eventually cornering him in a Forerunner construct. However, large numbers of Covenant and Promethean forces occupied the Spartans to give Jul enough time to escape through another portal. The Spartans desperately made their way through the constant firefights, even targeting air strikes on Jul's location.
Despite their efforts, Jul managed to make it through the teleporter. Unfortunately for him, however, while he was rushing to get away, he dropped what Crimson Team described as "the Didact's gift".
This infuriated Jul and he immediately sent numerous Phantom dropships to the science base Galileo, where Majestic took the item which he dropped for scientists to study. The Spartans were able to fend off the attacking forces and, when the area was clear, evacuated along with their prize aboard a Pelican dropship. His second-in command Gek 'Lhar complained that the humans now possess the soul of a Promethean Knight, Jul stated that they have made a good display of how valuable the package is.
Returning to the shrine, Jul communicates with Catherine Halsey, whom he was secretly in contact with since she arrived on Infinity and asked what she knew of the Librarian. Unfortunately, Halsey accidentally gave away her secret communique with Jul to Captain Thomas Lasky and Commander Sarah Palmer, though they didn't know who he was, and had her arrested. Jul was watching these events through some sort of holographic device.
Though this did not concern him as much because, at that moment, Glassman was able to activate a shield around the Librarian's shrine. As his subordinates bowed down in admiration, Jul assumed that the Librarian has been awakened and reach out to touch the shrine, but the shield repulsed him. Jul then noticed that Glassman had taken advantage of his distraction to run off and assumed that the human had tricked him. As his men went in search of Glassman, Gek promised to deal with him personally. However, Glassman managed to escape with the aid of Spartan-IV Gabriel Thorne, who was teleported to Requiem the same way Glassman was.
Sometime afterwards, Halsey managed to directly contact Jul, offering her assistance in uncovering the Librarian. However, she was cut off by Roland, Infinity's AI, who had managed to overcome the override protocol she used on him.
Soon afterwards, Prometheans boarded Infinity and kidnapped Halsey, bringing her to Jul. She managed to deactivate the shield around the shrine, as well as truly activating it. Suddenly, Halsey ran into the shrine, angering Jul, who shouts that he was to be the one to converse with the Librarian.
After Halsey acquires the "Janus Key" from the Librarian, she was launched back into Jul's clutches, where he relieved Catherine of one piece of the Key, not realizing she had the second. Soon, Spartan Gabriel Thorne had gained entry into the Shrine and assassinated one of Jul's bodyguards while using Gek 'Lhar's active camouflage unit, as Catherine quickly threw the second piece of the Key just as Sarah Palmer arrives. Startled, Jul summons the Promethean Knights to protect him, where Sarah attempts to assassinate Catherine but only managed a shot at her shoulder, Jul soon escapes with the help of a Promethean Knight with Catherine as his hostage.Jul soon ordered his forces to vacate Requiem as he set the planet to collide with the sun, intent on taking Infinity with Requiem. Fireteams Majestic and Crimson managed to deactivate the two artifacts on Requiem linking to the one on Infinity, freeing the ship and both sides escaped before the planet was consumed. In an unknown region of space, Jul accuses Halsey, whose left arm was amputated to keep her from bleeding to death, of betraying him by giving the other half of the Key to Thorne, but she's lucky she's still of use to him. Halsey defended that was before she knew the UNSC attempted to assassinate her and was willing to work with Jul to get her revenge.
Attack on Oban
In July 2558, Jul sent his forces to attack the human colony of Oban. The planet was a backwater with no strategic value, but Jul was convinced by Halsey that only a bold attack would draw the Infinity out to pursue them. With the Infinity in range, Halsey activated a Forerunner device to scramble the ship's Shaw-Fujikawa drive, preventing it from leaving a nearby star system. Jul's forces would wait on a nearby planet, hoping to ambush the ship to retrieve the other half of the Janus Key from the UNSC. 
- Raia 'Mdama - Jul's wife, who is in charge of much of the financial and agricultural planning in Bekan Keep. She died in the crash of the frigate Cleansing Truth.
- Naxan - Raia's grandbrother, who teaches the young children of the keep in combat and defense training. Although it is unconfirmed, Naxan is a possible swordsman, as he trains the youngsters in sword drills.
- His sons, Dural and Asum, though they do not associate with Jul due to the Sangheili custom of children not being permitted to know the identity of their true father to avoid nepotism.
- Gusay - Jul's personal aide.
- Forze 'Mdama - Jul's friend and fellow Shipmaster who is an elder of Curo Keep, who supports Jul's views on the Arbiter and humanity. He died in a crash of the frigate Cleansing Truth.
- Parg Vol - One of Jul's most trusted commanders during the Battle of Requiem. He was assassinated by the members of Spartan Fireteam Crimson while on Requiem.
- Gek 'Lhar - One of Jul's senior subordinates, responsible for watching Glassman and later tasked with tracking him down after his escape. He was killed by the members of Fireteam Majestic.
- He was, ironically, the only "family man" aboard the UNSC Port Stanley, the observation was made by one of the crew members named Mal.
- Jul had a habit of fiddling with his arum.
- Early in Jul's capture by the crew of the Port Stanley, Mal comments "It sounds like it's saying 'blarg,'" which is a reference to Red vs Blue (in which the aliens in that series are known to say "blarg" often), due to Karen Traviss being a huge fan of Rooster Teeth, the creators of Red vs. Blue.
- Another possible reference to Red vs. Blue is Jul's pronunciation of the name "Philiss," which is similar to the Project Freelancer AI, "F.I.L.S.S."
- Jul has adorned his armor with white handpaint. The prints consist of a Sangheili handprint with the Didact's symbol in the palm area.
- This symbol is available to use as your player's emblem in War Games.
- He wears a unique blue version of the Storm Zealot armor with a holographic symbol floating over the head.
- This symbol resembles the Forerunner Artillery from above.
- Between 2553 and 2558, Jul apparently learned to speak very sparse English. Since Sangheili are unable to pronounce the sound of the letter P very well, he pronounces Phillips' name as "Philiss" in the early days of his captivity. In the time since then, his pronunciation had improved to the point that he was able to say the word "progress" to Glassman without any obvious difficulty.
- In Awakening: The Art of Halo 4, his name is accidentally spelled Jul M'dama.
- He is nicknamed the "Black Elite" by UNSC forces.
- Jul is responsible for the destruction of the Forerunner shield world Requiem.
- Jul is actually briefly seen in the Halo 4 campaign level Forerunner. After the Cryptum's opening, the Elite nearest to the camera bows and shouts "Didact!" This Elite is Jul.
- Jul 'Mdama may be the Elite in the Mega Bloks set Forward Unto Dawn.
- In his captivity in Trevelyan, Jul was forced to use an explosive harness as the ones Brutes used on the Huragok from preventing them from being captured. Years later, in the second battle of Requiem he puts an explosive harness on Dr. Glassman ironically.
- Halo: Glasslands (First appearance)
- Halo: The Thursday War
- Halo: Mortal Dictata (Mentioned only)
- Halo 4
- Halo: Escalation
- Halo 5: Guardians