Osiris was resurrected in the Dark Age.¹ At some point, he began studying under the Iron Lords, namely Lord Felwinter.² On Felwinter’s advice, Osiris travelled to what would become the Last City in search of answers regarding the Traveler.³ There, he met Saint-14, whom he would eventually become romantically involved with.³⁴

Osiris fought alongside the Titans at the Battle of Six Fronts, after which Saint-14 recommended that Osiris be appointed as Vanguard Commander.⁵ Before his banishment, Osiris also mentored Ikora Rey.⁶

While Vanguard, Osiris grew tired of his role and began to question the motives of the Traveler.⁷⁸ He became fascinated by the nature of the Darkness and 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.⁷⁹

Osiris quickly became a popular, if unwilling, figure, with many Guardians and City-goers alike sharing his opinions on the Speaker and the Traveler.⁷ The Followers of Osiris grew around what Osiris viewed as a misinterpretation of his teachings.¹⁰ 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.¹⁰

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.⁷ Osiris was exiled by the Speaker, a decision backed by the other members of the Consensus, though he left the City willingly.¹¹¹² Osiris’ prophecies were deemed unsafe; the Speaker ordered Rey burn them, though she refused to do so, instead moving them to her private collection.¹³ After his exile, Osiris retreated to Mercury in order to study the Infinite Forest.⁶

Osiris left behind a number of adherents who remain loyal to him.¹⁴

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.¹⁵

Some time after the end of the Red War, Osiris was discovered by the Vex while exploring a simulation of the Vault of Glass.¹⁶ 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.¹⁶ After Sagira’s restoration and Panoptes’ defeat, Osiris was reunited with his Ghost, and they returned to the Forest.¹⁷

One of Osiris' followers, Brother Vance, was stationed in the Lighthouse on Mercury, along with several other cultists, prior to the planet being consumed by Darkness.¹⁶¹⁸

After returning to the Infinite Forest, Osiris began work on the Sundial: a device that would allow him to traverse the Forest rapidly, find the point of Saint-14’s death at the hands of the Vex, and prevent it from ever happening.¹⁹ The device did not work, despite Osiris’ best attempts; he shut it down and hid it.¹⁹ Shortly after the slaying of the Undying Mind, Psions uncovered the Sundial and attempted to use it to revert to the Red War.²⁰²¹ Osiris used the opportunity to teach the Guardian how to use the Sundial, saving Saint-14 and thwarting the plans of the Psions.²²²³

Having successfully returned Saint to life, Osiris left his partner in charge of the Trials of Osiris and went to speak to Rasputin.²⁴ Rasputin directed him to the outer edge of the solar system, where he found a strange seed.²⁵ Queen Mara Sov then sent Osiris a message instructing him to plant the seed.²⁶

After the Traveler reawoke, Osiris investigated the planets that the Darkness engulfed.⁴ Finding nothing significant, he turned his search to Hive signals — strange monoliths that had grown in the Tangled Shore. This was a trap from the Hive goddess of war, Xivu Arath; when Osiris' investigations led him to the remains of Crota's brood deep within the Moon, Xivu struck.²⁷ Osiris would have died, but Sagira sacrificed herself to save his life.²⁷²⁸

Savathûn’s Deception

Soon after Sagira’s death, Savathûn began impersonating Osiris.²⁹ During this time, Osiris was partially aware of Savathûn’s actions but was unable to warn anyone of the deception.³⁰

Under the guise of a grieving Osiris, Savathûn continued hunting the High Celebrant of Xivu Arath.²⁸³¹ Zavala sent the Guardian to recover Osiris, which led to the Guardian encountering the Crow for the first time.³¹ A disguised Savathûn assisted Crow and the Guardian with eliminating the High Celebrant; she also served as a mentor figure to Crow.³²³³

Unaware of Savathûn’s deception, Ikora became concerned for Osiris’ health and asked that Zavala take him on as an advisor.³⁴

In this capacity, Savathûn accompanied Zavala to a meeting with Caiatl, who sought to ally the Cabal with the City after the fall of her homeworld Torobatl; Savathûn advised Zavala against such an alliance.³⁵ In response, Caiatl launched an incursion in Sol.³⁶ Savathûn oversaw the Guardian’s destruction of Caiatl’s War Council alongside Zavala and Lord Saladin.³⁶³⁷

As Osiris, Savathûn also advised the Guardian as they boarded the Glykon in search of a missing Guardian.³⁸ After the Guardian discovered the Crown of Sorrow, she expressed a desire for it to be recovered from the ship, despite Caiatl’s protests that it be destroyed.³⁹

When the Endless Night first engulfed the City, Savathûn was among those who recommended seeking out the Sacred Splicer Mithrax.⁴⁰ With Mithrax, she utilized her disguise in order to oversee the Guardian’s incursions into the Vex network.⁴¹ She also helped the Guardian to find and destroy Quria, ending the Endless Night.⁴²

During the Endless Night, Savathûn became involved in Lakshmi’s plan to overthrow the Vanguard.⁴³⁴⁴⁴⁵ She also attempted to find the Cabal Light suppressor that had been used on Zavala’s Ghost.⁴⁶ When the Vex attacked Botza, Savathûn left the City.⁴⁷

Shortly after Quria’s defeat, Ikora issued a warrant for Osiris’ arrest, citing a belief that he had been involved in Lakshmi-2’s attack on the Eliksni.²⁹ Saint-14 and the Guardian travelled to the Dreaming City to collect him, where they found him with Mara Sov. Savathûn then transformed into a crystalized cocoon, revealing that she had taken control of Osiris months ago. However, she assured the Guardian that she would relinquish control of Osiris in exchange for assistance with removing her Worm.²⁹⁴⁸