Archaon is the cruelest joke the Dark Gods ever told, and he knows it, and the knowing is the engine of everything. In the World-that-Was — the world from whose ashes the Mortal Realms rose — he was a knight sworn to Sigmar, faithful beyond fanaticism, until he uncovered a prophecy naming him the doom of all he served. Every attempt to outrun that fate marched him deeper into it, and in the end he embraced the role with a convert's fury: he claimed the regalia of the Everchosen through one impossible quest after another, marshaled the final great host of Chaos, and made the prophecy true. The old world ended. Archaon did not.
No being in the realms carries such an arsenal of history. He wears the Armour of Morkar, plate of the first Everchosen; he bears the Slayer of Kings, a blade with the daemon U'zuhl bound raging inside it and thirsting for the necks of monarchs; the Eye of Sheerian sifts the futures around him for treachery; and beneath him moves Dorghar, the Steed of the Apocalypse, a nightmare whose three heads snap and argue with the stolen essence of greater daemons. He is marked by all four Dark Gods at once — an honor that annihilates anyone else who receives it — and above his own eyes opens a third, which the wise refuse to meet.
From the Varanspire, the fortress at the heart of the Eightpoints where arcways open onto every Mortal Realm, Archaon prosecutes his long war against Sigmar with a patience that unnerves even his own pantheon. It should. The Everchosen serves the gods the way a drawn blade serves the hand — for exactly as long as it is pointed where the blade agrees to point. He despises the powers that exalted him with the same totality he once brought to worshipping their enemy, and every triumph he delivers to Chaos is also a stone laid in a colder project: the casting down of every throne, celestial and infernal alike. In the deep heart of the Varanspire, it is said, a throne stands empty. Archaon is very clear that it is not waiting for a god.