|Faction||Forces of Order|
|Rank||Priest of Order|
Thadon is the Duke of Mania. His use of mind-altering substances is well-known. He lives in House Mania's wing of Sheogorath's Palace. He's well recognized to be a 'Master of Merriment', and to be fond of over-indulgence.
Thadon spends much of his time in his throne room or painting in the Halcyon Conservatory. Speaking to him during the quest Understanding Madness will activate the quest Addiction. He is addicted to Felldew, found in certain Elytra.
Later, if the Hero chooses to become Duke or Duchess of Dementia, he will appear to them and Sheogorath, and will announce a threat to the Prince of Madness. Then he leaves to join Jyggalag, and aid him in the Greymarch. It is implied in the quests Addiction and The Lady of Paranoia that Thadon and Syl were together for a short time.
- The Elder Scrolls IV: Shivering Isles' (First appearance)