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Ushering Dusk was a San'Shyuum Reformist during the War of Beginnings. He served as part of the Keepers of the Dawn, a group that led the San'Shyuum from aboard their Forerunner Dreadnought, and he was one of the first Reformist leaders to propose a truce with the Sangheili. Because of this, Dusk was ultimately assassinated by secret order of Pervading Stone, the leader of the Keepers of the Dawn.
War of Beginnings
Ushering Dusk served as part of the Keepers of the Dawn—the first San'Shyuum to be called Prophets—during the War of Beginnings alongside Breaking Shadow and Pervading Stone, their leader. Driven by the desire to avenge the death of his father at the battle of Ulgethon, Pervading Stone spent years leading the Reformists as they laid waste to Sangheili colonies and outposts. Following the events at Codisfold when several Sangheili infiltration teams breached the Forerunner Dreadnought and slew thousands of San'Shyuum, many began to shift their opinion on the war. Realizing that they were no longer untouchable, Ushering Dusk and Breaking Shadow began to lobby for peace. In response, Pervading Stone secretly had Dusk assassinated to remove him as an obstacle.
Ushering Dusk would not be the only San'Shyuum silenced by Stone as he continued to mercilessly assault the Sangheili. Even after it was discovered that the Sangheili had amended their beliefs which had sparked this war and begun to use Forerunner weapons for defense, Stone refused to entertain the idea of peace. Eventually, after the San'Shyuum discovered and attacked the Sangheili homeworld of Sanghelios, the Sangheili responded by turning their Forerunner-derived weaponry against the Dreadnought, shooting it down on Suban where it was held in place with gravity anchors, effectively trapping the San'Shyuum inside. Despite this, Pervading Stone refused to submit to a truce with the Sangheili. As a result, Breaking Shadow led a swift and violent coup against Stone, ending with his assassination. Then, in 852 BCE, Shadow sent an unarmed delegation to meet with the Sangheili. Breaking Shadow and First Kaidon Pelahsar the Strident forged a tenuous alliance, forgiving the other's species for their past crimes. This was soon formalized in the Writ of Union, the founding document of the Covenant, finally bringing on the peace for which Ushering Dusk had given his life.