Shelden claims to be the mayor because he showed up first. Even though nobody ever attempts to take over, no one really sees him as the mayor, either.
He is one of the first people the Hero meets in Passwall; he is seen heading up to the Gatekeeper with Felas Sarandas to watch a group of adventurers attempt to fight him. Besides some small tidbits of advice, he has very little to provide the Hero.
During Retaking the Fringe he will be seen again inside Xeddefen hiding from the Forces of Order. If he is allowed to follow the Hero, he will be of some use until they get split up. If he is told he needs to leave on his own, he will probably be killed by one of the Knights of Order or die during the collapse of the ruins.
The Hero, when first entering the portal on the island in the Niben Bay after being briefed by Haskill at the end of A Strange Door, will come to the town of Passwall. In town, the Hero will find two characters talking, the mayor of Passwall and a dark elf.
Thadon or Lady Syl will also tell Sheogorath that the Fringe has been taken. Sheogorath is delighted, as this is a new turn of events, and sends the Hero to investigate. They will eventually go to the ruin Xeddefen.
Xeddefen is a fairly large ruin. Look for buttons in walls, traps, and watch the map for the beginnings of hallways behind secret doors. Proceed to the Great Chamber where they will discover Shelden, the self-appointed mayor of Passwall, sneaking through the halls.
- Through the Fringe of Madness
"Hello, I'm Shelden. I've been here the longest. That's why I'm mayor of Passwall. That, and because I'm the best at being in charge. Welcome to my town!"
- Gatekeeper "He guards the Gates of Madness. See for yourself. He's about to destroy a party of adventurers."
- "He guards the Gates of Madness. Don't get too close to him. He'll kill you, and it will leave a mess in my town. Jayred Ice-Veins wants to kill the Gatekeeper. Sounds like suicide to me."
- Gates of Madness "They say the keys are sewn up in the Gatekeeper's body. Basically, that means you're not getting in."
- Passwall "The place was pretty deserted when I got here. Of course, once I was here, others followed. Can't say I blame them."
After killing the Gatekeeper:
- Gatekeeper "I'm glad you took my advice and killed him. I always knew it could be done. What would people do without me?"
- Gates of Madness "I think I'll stay here for awhile. Someone has to run this town. I'm certainly the best qualified."
- Retaking the Fringe
"It's... it's you! I remember you. What are you doing down here? How did you get past the Knights? When they attacked, I ran from Passwall. They didn't say a word, they just started killing! The screams! By the staff, you can't imagine the screams! Felas and I slipped down here thinking that we'd be safe. But, no! We landed right in the middle of them! Felas ran off with them and left me to die! Me! That ingrate! Disloyal cur! Imagine, leaving me here all alone!"
- They took Felas? "I didn't say they took him -- he went with them! I've heard his voice a few times around here, I think... I think he joined them!"
- Why haven't you tried to escape? "Every time I look for a way out, I get twisted around and end up back here. But I'm too smart for them. You seem to have no trouble, though. Look at you, barely a scratch! You'd be the perfect person to protect me!"
- Maybe you're just a coward. "Oh, sorry. I wasn't aware that being a courageous hero was a requirement around here. Look, you may be a scamp's ass, but I'm offering you the chance to be the hero of Passwall. Escort me out of here, protect me, get me home, and those people will praise you more than you can imagine."
- It's very dangerous here. "This place is a nightmare! Knights everywhere, these priests, and whatever they've done to Felas! Listen. Those people in Passwall need me. Can you imagine how they'd ever get along if I died down here?"
- Um... Sure. Come with me. "I'll do what I can to help. I... I like to hurt things. Maybe I can hurt these damned knights."
- I don't think so. You stay here. "What? Here? Are you kidding? I'm not staying here! If you don't want to help me, fine. I'll get out of here on my own."
While following the Hero:
"Can we get out of here?"
- Follow me. "What do you think I'm doing? I'm not sticking this close to you because I enjoy your pleasing aroma."
- Stay here, I'll be back. "Stay here? What's wrong with you? I'll be killed! Take me with you! Please?"
If told to stay:
"Can we get out of here?"
- Follow me. "Let's just hurry this up... please?"
- Stay here, I'll be back. "What do you think I'm standing around here for? It isn't because I like being in this place!"
- Never mind. "Right then. You lead the way -- just try not to get us killed. Well, try not to get ME killed."
Upon being separated:
"I don't think this thing is going to open again. You are the worst escort in history. I'll find another way out. Get going!"
Upon finding Shelden behind a closed gate:
"Hey, is that you? I hear something over there.... Well look at this, I found the easy road. How are things going over there?"
After getting out of Xeddefen:
"I'm going to stay here and help rebuild the place. These fools need me."
- Through the Fringe of Madness
Shelden: "I tried to warn them."
Felas: "Maybe they're just confused."
Shelden: "They should have listened to me!"
Felas: "We'll be swimming in blood soon. Yuck."
Shelden: "Let's go watch!"
Felas: "Just as long as we don't catch any of their diseases. Adventurers always get strange diseases."
Shelden: "Come on, it'll be fun watching them get knocked around up there. I'll lead, you'll follow."
Felas: "Just don't get any blood on me!"
[At the gatekeeper]
Shelden: "They should have listened to me."
Felas: "Oh no. They're bleeding all over the place!"
Shelden: "Dead. I warned them, didn't I?"
Felas: "Yuck. Look at all the blood and gore. I'm getting out of here."
- "Everything is gone. What a shame." —During "Rebuilding the Gatekeeper"
- "Things are coming along nicely here. Soon enough, they'll have no choice but to do everything I say." —During "Rebuilding the Gatekeeper"
- There is amber and madness ore in Shelden's House.
- If the amber and madness ores are taken it must be before doing the quest "Retaking the Fringe."
- There are also alchemical ingredients in his house.
- Shelden is wearing Purple Finery.