According to rumors, he was once a zealous Templar of Sigmar, devoted to battling the menace of Chaos. He read ancient manuscripts written by Necrodomo the Insane, which contained blasphemies about the religion of Sigmar and the nature of Chaos. Screaming in rage, he called the gods liars and burned down the temple and manuscript. He then hunted down and killed his entire family. Adopting the name Archaon, he travelled north towards the Chaos Wastes. There he offered himself to the Chaos Gods as a tool of destruction. His lifespan unnaturally extended by his Chaos patrons, Archaon spent the next century gathering six artefacts of Chaos:
- The Mark of Chaos: This shows the bearer to be the chosen of all four Chaos Gods. It was received at the Altar of Ultimate Darkness in Naggaroth.
- The Armour of Morkar: Extremely resilient and dark black, this armour was worn by the first Everchosen of Chaos, who was killed by Sigmar.
- The Eye of Sheerian: When mounted in the Crown, the Eye grants the bearer potent powers of prophecy and omniscience. It was taken from the hoard of the Chaos Dragon Flamefang.
- Dorghar, Steed of the Apocalypse: A massive, daemonic horse, Dorghar was claimed at the Gates of Chaos, stolen from the Daemon Lord Agrammon.
- The Slayer of Kings: A huge blade with the raging soul of a captive daemon, U'zhul bound inside it. Archaon took it from the hands of a Dragon Ogre.
- The Crown of Domination: A symbol of absolute authority to the forces of Chaos and sheer total to their foes. Found in the First Shrine to Chaos at the Worlds Edge Mountains. Location learned from Be'lakor. Archaon fought a Bloodthirster (Greater Daemon of Khorne) single-handedly to obtain it.
Upon retrieving the Crown, Be'lakor performed the coronation that made Archaon the Lord of the End Times. Leading a vast army of Chaos warbands united under his banner, Archaon marched on Empire from the north, while his herald, Vardek Crom, marched from the east, over the World's Edge Mountains. Archaon killed Volkmar the Grim, Grand Theogonist of Sigmar, with one blow from the Slayer of Kings by unleashing the power of U'zuhl, the daemon bound within it.
Archaon's ultimate goal during the Storm of Chaos was to storm Middenheim, enter the Temple of Ulric, and corrupt the Eternal Flame with his own essence, extinguishing it and ushering in the End Times. After ruining two provinces of The Empire and ravaging a third, Archaon battled Valten, Exalted of Sigmar in single combat. Valten taking a seemingly mortal blow, Archaon was then hit in the head by Huss but sent Huss flying with a back hand blow. Archeon was then blind-sided by Grimgor Ironhide, the Orc warlord. Grimgor raised his weapon for a death blow, but merely proclaimed, "Grimgor iz da best!" and left Archaon on the ground. Archaon is rumoured to have retreated to the Chaos Wastes, leaving the Empire in shambles.