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Master Rahool is an Awoken Cryptarch found at the Tower's main plaza. Rahool will decode any Engrams that the player has for free. In Destiny, he will also offer to exchange a number of legendary engrams for Legendary Marks.
Besides being a Cryptarch, Master Rahool is also a historian and linguist. He makes mention of various artifacts from the Golden Age and beyond, particularly various religious texts.
The Rising Darkness
Rahool briefed a Guardian during their mission to the Moon to destroy the sword of Crota, Son of Oryx. He explained to them how the sword drained the Light from the Guardians it killed, and that the sword was guarded by the Swarm Princes in the Hive's fortress. After the Guardian succeeded in killing the Princes and destroying the sword, Rahool congratulated them and noted that while many believed Crota would one day awaken and more weapons would be forged in his name, he believed that the destruction of the Hive Prince's sword brought humanity one step closer to reclaiming the Moon and defeating the Hive.
When that same Guardian destroyed a Shrine of Oryx on the Moon, Rahool contacted him and noted that the exiled Warlock Vanguard Osiris had spoken of and feared the Hive god called Oryx and that his agents hunted for the shrines. He speculated that if Osiris still lived, he would know of the Guardian's heroic deed.
After the Guardian killed a Cyclops and analyzed its mind core at a research station in the Ishtar Academy on Venus, they brought the data to Rahool for decryption. Rahool examined the Vex code and provided the Guardian with the information they needed to summon a Gate Lord. He asked the Guardian to return with other "amusing puzzles" in the future if they survived their fight.
Rahool soon requested that the Guardian secure the Ishtar Academy's archives and prevent the Fallen from looting it, as it contained the work of some of the Golden Age's greatest minds and the Cryptarchs wished to study the data within. The Guardian succeeded in driving the House of Winter from the Academy's archives and their Ghost downloaded its contents for the Cryptarchs to study. Rahool was overjoyed by the information provided to them, especially about the Vex and the Vault of Glass, and he hoped to use this newfound knowledge to finally crack the Vault's secrets.
Upon learning that the Guardian had breached the Cabal's Exclusion Zone on Mars, Rahool requested that they travel to Freehold and explore the ruins of Clovis Bray's offices there. As they journeyed to Mars, Rahool contacted them and explained that the Cryptarchy had wanted to gain access to Freehold's secrets for years and begged them to prevent the Cabal from destroying any of its technological wonders. While the Guardian prevented the Cabal from gaining access to technology there, the Warmind Rasputin took control of the machines there and locked out the Vanguard and Cabal from accessing them. Rahool was pleased the Cabal were stopped, but disappointed that Rasputin was not sharing the information within. Despite that setback, he remained optimistic about the other technology within Clovis Bray that humanity could access once more and hoped it signified the dawn of a new age for the City.
The Taken War
Upon learning of Queen Mara Sov's supposed demise during the Battle of Saturn at the onset of the Taken War, Rahool decided to use the instability the Reef was experiencing as an opportunity to open new lines of communication between the City's cryptarchy and the Reef's. He wrote a letter to Master Ives expressing his condolences for the loss of Mara, but then informed Ives that he and the other City cryptarchs had been withholding knowledge about the history of Earth and its colonies, along with other sensitive secrets about the origins of the Awoken and others like them, from the Reef due to their fears of what the Queen would have done with that information. He suggested that with the Queen gone, they would be willing to share that knowledge for the Reef's own secrets and the promise of working together in future studies.
A New Golden Age?
During the Red War, Master Rahool fortunately survived the fall of the Tower and the Red Legion's invasion of the Last City. Once the City was liberated, Rahool returned to his duties at the new Tower, lending his decryption skills to the Guardians. Not long after returning to the City, Rahool received a reply to the message he had sent more than two years ago to Master Ives. The Reef cryptarch insulted Rahool for his blatant attempt to take advantage of the Reef's grief and asserted that the Reef held far greater knowledge than anything that could be found on Earth, although he accepted the offer to exchange information between the two cryptarchies.
A year after the end of the Red War, Rahool watched discreetly as Paladin Kamala Rior of the Reef pleaded with Guardians in the Tower plaza to provide aid to the Awoken in the bid to retake the Dreaming City from the Taken. During the Festival of the Lost, Rahool learned from Amanda Holliday that Master Ives had been murdered in the Reef by the Fallen. Despite the animosity between them, Rahool grieved for his fellow cryptarch and helped Amanda and the Young Wolf find leads that led to the location of Ives murderer, a Captain of the House of Dusk named Kikliss.
Clash of the Chosen
When the Imperial Cabal led by Empress Caiatl began their incursion into the Sol System, Rahool was assigned by Commander Zavala to Operation Haystack, which was designed to intercept and translate Cabal communications for information on their new foes. Amongst the intercepted data, Rahool flagged information on Caiatl's diet as important, noting that the Empress was serving dishes at formal occasions that had their origins in lower classes of Cabal society. Although the translation and interception were incomplete, Rahool speculated that this was a sign of Caiatl attempting to differentiate herself from her father Calus's opulence and Dominus Ghaul's utilitarianism.
Rahool was later presented with a intercepted distress call from the Hunter Katabasis. Upon examining the distress signal Rahool determined that it had been exposed to the Darkness in some manner. He subsequently traced the origin of the call to the Glykon Volatus a seemingly abandoned and derelict Cabal Carrier in the Reef aligned with the deposed Emperor Calus.
List of appearances