The Argus storyline starts in patch 7.3.0 and deals with the heroes of Azeroth traveling to Argus, the former homeworld of the eredar before their corruption by Sargeras, to end the threat of the Burning Legion once and for all.
Led by Prophet Velen, the champions of Azeroth embarked on a journey to the shattered world of Argus, home of the demonic Burning Legion, to put an end to their crusade against life. There, they joined forces with the Army of the Light—a host of Lightforged warriors who spent millenia fighting the Legion across the stars, and whose ranks included the legendary paladin Turalyon and ranger-captain Alleria Windrunner. Together with the champions of Azeroth, the Army of the Light mustered their scattered forces and embarked on a desperate quest to storm the Legion’s seat of power: Antorus, the Burning Throne. There, the heroes discovered that the fallen titan Sargeras had corrupted not only the soul of the world of Argus, but the titan Pantheon as well. After a tremendous struggle, the heroes of Azeroth defeated the soul of Argus and freed the titans, who imprisoned Sargeras for his transgressions—and appointed Illidan Stormrage as his jailor. As a last act of defiance, the Dark Titan plunged his sword into Azeroth, inflicting a deep wound in the planet that would leave her fate uncertain...