The Roots of Madness

Overview
Faction: Shivering Isles Main Quest Prerequisites: Symbols of Office Quest Giver: Haskill Reward: Staff of Sheogorath, quest The End of Order

Background
Sheogorath has asked you to be his champion and defend the Shivering Isles from Jyggalag and the onset of the Greymarch. Sheogorath also revealed that he is, in fact, Jyggalag, and will eventually destroy his own kingdom. During the last quest, Symbols of Office, Sheogorath vanished is now presumably Jyggalag. Haskill then told you that it was still possible to defeat Jyggalag, but it would require you ascending to the Throne of the Madgod. You would need to rebuild the Staff of Sheogorath before that was possible, however. So you had successfully rebuilt the staff, and now you are ready to recharge it in the Palace's Font of Madness. Finding it overgrown in Order Crystals, you speak to Haskill.

Walkthrough
Haskill tells you that Jyggalag has poisoned the font by fouling the pools of Mania and Dementia below the fountain itself. The pools are where the insanity of the Shivering Isles' inhabitants settles. You will need to clear both the Pool of Mania and the Pool of Dementia before you can finish crafting the Staff of Sheogorath.

The entrance to the Fountainhead is behind the throne. The Gnarl Cultivators that inhabit the Fountainhead are tame and will not attack. However, you will also encounter standard Gnarls that will need to be dispatched before you can proceed. Hostile Gnarls can be identified by their blueish-silver glow.

Explore the Fountainhead until you find two small pools that Priests of Order are actively poisoning. Kill them and take their Shards of Order. The Shards are necessary to break the seals on certain root doors in the Fountainhead. Once you have two Shards, follow the red arrows to the two main pools: the Pool of Mania and the Pool of Dementia. These pools are defended by more Priests of Order. At the final pool you assault, you will also find Lady Syl (or Lord Thadon, depending on your choice in the quest Ritual of Accession). Once you have killed everyone and restored the pools, return to the Throne Room. The crystals from the Font of Madness will be gone, and activating it will give you the fully-functional Staff of Sheogorath.

This will end your current quest and begin your final quest, The End of Order

Journal entries

 * After attempting to re-power the Staff of Sheogorath in the Font of Madness:
 * Something is wrong with the Font of Madness. It won't accept the Staff of Sheogorath and imbue it with power as Dyus described.  Perhaps Haskill will know what's wrong with it.

After speaking to Haskill:
 * The Font of Madness has been poisoned by Order! If it becomes fully Ordered, the realm is lost and Jyggalag has won.  Haskill suspects that Order has somehow gained access to the Pools of Madness that nourish the Font.  I need to enter the Fountainhead beneath the tree before it is too late.

After killing the defending priests of Order and Syl (or Thadon) and entering both pools:
 * I have immersed my Staff in the Font of Madness. I have gained the power of Sheogorath.