- "This ends as it always does. Order shall reign!" — Jyggalag
The Greymarch is an event that happens at the end of every era in the Shivering Isles, intended to wipe out the entire realm so that Sheogorath must rebuild it. It starts with the appearance of large crystalline obelisks that emerge from the ground. These obelisks produce and are the power source of Jyggalag's minions, the Knights and Priests of Order. The Greymarch is the end of the cycle that the Daedric Princes cursed Jyggalag to endure every era. It is characterized by irresistible brute force, with very little in the way of subterfuge or any variation to previous methods.
It is unknown when the Greymarch first began. Long ago, before recorded time, the Daedric Prince of Order, Jyggalag, was growing in power and influence, spreading across realms and dimensions. The other Princes, growing fearful of Jyggalag's power, cursed him to become an embodiment of what he hated most: chaos and madness. The Prince of Madness, Sheogorath, was born that day. Sheogorath turned Jyggalag's domain into the Shivering Isles, a realm reflecting his madness, and once every era he would become Jyggalag once more to destroy the Isles and reclaim his realm. With that accomplished, he would transform back into Sheogorath, who would be left to rebuild his realm.
As part of the Greymarch, Sheogorath summons a mortal champion to the Isles to fight back against the forces of Order. When Sheogorath disappears to become Jyggalag, this mortal mantles the role of the Mad God for a final battle with Jyggalag. If defeated, the Prince of Order believes himself free of his curse and vows to depart the realm, leaving the Isles and the title of Sheogorath to the mortal. However, this false hope is seemingly part of the curse, as Jyggalag is not freed. Instead, the mortal soul of the previous Mad God will become Haskill, a Vestige chamberlain forced to serve the new Sheogorath.
In 3E 433, the Champion of Cyrodiil arrived in the Isles to play the role of mortal champion, mantling Sheogorath and defeating Jyggalag and the forces of Order. It is possible that Arden-Sul was a mortal who had mantled Sheogorath previously, as suggested at the time by the beliefs of the Zealots and Heretics.
Different incarnations of Sheogorath and Haskill seemingly have differing recollections of the Greymarch. Some misremember the events of past Greymarches and believe that a mortal champion is a novel approach, while others have very little knowledge of what the Greymarch even is. As Sheogorath, the Champion of Cyrodiil appeared to eventually realize the true nature of the cycle, stating that the title of Mad God is one which "gets passed down from me to myself every few thousand years". Few mortal inhabitants of the Isles ever live to see a second Greymarch; although they do not age without Sheogorath's will, few seem to survive the event.
- Sheogorath states that the Greymarch happens at the end of every era, but no indication is given that these eras are the same as Tamrielic Eras. Some sources state that a Greymarch occurs once every 1,000 years, while others claim several thousand.
- Sheogorath's dialogue in Shivering Isles
- Haskill's dialogue in Shivering Isles
- The Predecessors — Yngvar the Wanderer
- Jyggalag's dialogue in Shivering Isles
- Events of the Shivering Isles
- Chamberlain Haskill Answers Your Questions — Chamberlain Haskill
- Pensamentos Heréticos
- Sheogorath's dialogue in Skyrim