Osiris fought alongside the Titans at the Battle of Six Fronts, after which Saint-14 recommended that Osiris be appointed as Vanguard Commander. Before his banishment, Osiris also mentored Ikora Rey.1
While Vanguard, Osiris grew tired of his role and began to question the motives of the Traveler. He became fascinated by the nature of the Darkness, and he pursued a number of controversial avenues to further his understanding, including Ahamkara-lore and thanatonautics. He was especially interested in understanding Oryx and the Vex.2
Osiris quickly became a popular, if unwilling, figure, with many Guardians and City-goers alike sharing his opinions on the Speaker and the Traveler.2 The Followers of Osiris grew around what Osiris viewed as a misinterpretation of his teachings. However, as Osiris continued to entertain them, their numbers increased. The popularity of his “forbidden truths” only grew with the publication of the Prophecies of Osiris.3
His questioning of the Speaker and the Traveler was considered disloyal, and the sway that he held over Guardians was considered dangerous, as was the divisiveness of his beliefs.2 Osiris was exiled by the Speaker, a decision backed by the other members of the Consensus, though he left the City willingly.4 5 Osiris’ prophecies were deemed unsafe, and the Speaker ordered Rey burn them, though she refused to do so, instead moving them to her private collection.6 After his exile, Osiris retreated to Mercury in order to study the Infinite Forest.1
Osiris left behind a number of adherents who remain loyal to him. His study of the Vex led him to set up a number of camps across Mercury, including The Lighthouse.
After the release of Skolas, two Guardians visited the Queen of the Reef and asked for aid in defeating Oryx. It is believed that these Guardians were Eris Morn and Osiris, but this has not been confirmed.7
Some time after the end of the Red War, Osiris was discovered by the Vex while exploring a simulation of the Vault of Glass.8 He flung his Ghost, Sagira, through a Vex portal to try and guarantee her escape. Sagira was injured by a Vex rifle, rendering her inoperable; a member of Ikora’s Hidden discovered her on Mercury and returned her to the Tower.8 After Sagira’s restoration and Panoptes’ defeat, Osiris was reunited with his Ghost, and they returned to the Forest.
One of Osiris' followers, Brother Vance, is stationed in the Lighthouse on Mercury, along with several other cultists.8
Join Baxter and Purple Chimera as they discuss Osiris, the exiled Warlock Vanguard.