Haskill is the first person encountered on the Shivering Isles, and will ask if the Hero wishes to enter the Realm of Sheogorath. If this request is declined, the Door to Cyrodiil will be the only location accessible.
Later on, the Hero will be able to summon him for no cost to magicka (Haskill can only be summoned inside Sheogorath's Realm). While he will not aid the Hero in battle, he will offer information and help on quests (although he is frequently and easily annoyed by the Hero throughout the entire course of the Shivering Isles questline).
When the questline is finished, he will be a source of income via small missions that call for the Hero to defend the Isles, and as a purveyor of entertainment. Haskill cannot be harmed; weapons will go through him with no adverse effect, as with Sheogorath in The Elder Scrolls V: Skyrim.
"Another mortal. Quaint." "Let's be civil, shall we? Please, have a seat." "Do sit down." "Please, sit." "Take a seat, please."
After sitting down:
"Yes. What can I do for you? I imagine you're here about the door?"
Strange Door"Yes. You have entered and now you are here. Amazing. Truly."
Who are you?"I am Haskill, Chamberlain to the Lord Sheogorath."
What is this place?"You approach the Shivering Isles. Through the door behind me lies the realm of Sheogorath, Prince of Madness, Lord of the Never-There."
Why did that door appear in Cyrodiil?"Because my Lord wills it to be so. It poses no danger to Mundus; no compact has been violated. It is a doorway, an invitation. Perhaps you will accept it for what it is."
What do you want with me?"For you? I do not know. My Lord seeks a mortal to act as His Champion. As for His intent... to attempt to fathom it is a foolish endeavor. His will is His own; His reality follows suit. You are here because you chose to enter; you were not summoned."
And the people outside?"They entered this Realm, and were ill prepared. Their minds are now the property of my Lord."
How can they be cured?"Cured? You speak as if they are diseased. They live now in another state of being. Perhaps it is you who needs a cure."
What happens now?"You do as you will. You may leave the way you entered. Your life will be none the worse for your time spent here. Or, you may continue onward, through the door behind me. If you can pass the Gates of Madness, perhaps the Lord Sheogorath will find a use for you."
And if I go through the door?"Who is to say? There are always choices to be made. The Realm of Madness is no different in that regard. Your choices are your own. Enter or do not, but make your decision. I've other duties to which I must attend. Speak with me again when you have made up your mind. The anticipation is almost too much to bear."
If spoken to again:
"Well? Have you made up your mind? The tension is almost palpable."
No, thanks."Hmmm. Not surprising. Well, if you change your mind, and the position is still available, come speak with me again. I'd so enjoy that...."
I'll do it."Fine. I'm sure my Lord will be most pleased, assuming you ever manage to see Him. You'll want to pass through the Gates of Madness. Oh, and mind the Gatekeeper. He dislikes strangers to the Realm. Enjoy your stay."
"So, you've managed to kill the Gatekeeper. Pity. Well, you'll now be able to enter the Realm proper. You'll notice there are two doors. One leads to the lands of Mania. The other to Dementia. Enter through either one. The lands are quite distinct, but both are Sheogorath's domain. You'll want to seek out Lord Sheogorath. I believe He has plans for you. Try not to disappoint Him."
Dementia"The lands of Dementia reflect the darker side of its residents. IT is easy to get lost among the tangle of roots growing out of the ground. If you wish to meet Dementia's citizens, seek them out in Deepwallow or Fellmoor. I'm sure they'll welcome one such as you with open arms."
Gates of Madness"The doorways into the Realm proper. You may enet through either one. Really, it depends on which aspect of the Realm more suits your disposition. As I've said, all choices have consequences, but don't trouble yourself too much with your decision. All those that enter the Realm are forever changed, but some believe it is for the better. A good portion of them, at least."
Mania"The lands of Mania are bright, vibrant, and full of color. You'll find its inhabitants reflect the land itself. If you wish to meet the residents of Mania, you'll find them in the settlements of Hale and Highcross. Take care, though. Though the citizens and creatures of Mania are colorful, they can often be quite deadly. I'm sure you can handle it, though."
New Sheoth"It is, of course, the capital of the Shivering Isles. It is divided into Bliss, Crucible, and the Palace districts."
Sheogorath"He is the Prince of Madness. The ruler of the Shivering Isles. It is by His will that we exist in this place. He is our Lord and Master. You'll want to speak with Him soon, as I believe he has plans for you. You will find Him in New Sheoth, in His palace. It is best not to make Lord Sheogorath wait. His whims are fleeting, and should He decide you are no longer necessary, it would be to your detriment."
Shivering Isles"You will enter soon, I imagine, through the Gates of Madness and into the lands of Mania and Dementia. It is the Realm of Lord Sheogorath. It is what He wills it to be. The trees bloom according to His whim, and the wind blows at His command. Tread lightly into the Isles. It is not a place suited to all mortals. But, I'm sure you'll do fine."