Derethil and the Wandersail

Wandersail was a majestic vessel intended to do what none had dared before: sail the seas through Burn's Breath. She was commissioned by Derethil and he took her westward, into the Endless Ocean, seeking the origin of the world. The Wandersail was nearly destroyed, shipwrecked on a ring of small islands surrounding an enormous whirlpool, where (it was said) the ocean drains. Wandersail was repaired in the local shipyards. Eventually, Derethil and his remaining crew set sail again on the Wandersail, using the momentum of the whirlpool to spin them out and away from the islands. It's unknown if Wandersail and its crew survived the trip home, but some stories say they did.

Summary

Derethil is well known in some lands, though I have heard him spoken of less here in the East. He was a king during the shadowdays, the time before memory. A powerful man. Commander of thousands, leader of tens of thousands. Tall, regal, blessed with fair skin and fairer eyes. He was a man to envy. Derethil fought the Voidbringers during the days of the Heralds and Radiants. When there was finally peace, he found he was not content. His eyes always turned westward, toward the great open sea. He commissioned the finest ship men had ever known, a majestic vessel intended to do what none had dared before: sail through Burn's Breath.
Derethil’s goal, was to seek the origin of the Voidbringers, the place where they had been spawned. Many called him a fool, yet he could not hold himself back. He named the vessel the Wandersail and gathered a crew of the bravest of sailors. Then, on a day when a great storm brewed, this ship cast off. Riding out into the ocean, the sail hung wide, like arms open to the stormwinds.
The Wandersail ran aground and was nearly destroyed, but Derethil and most of his sailors survived. They found themselves on a ring of small islands surrounding an enormous whirlpool, where, it is said, the ocean drains. Derethil and his men were greeted by a strange people with long, limber bodies who wore robes of single color and shells in their hair unlike any that grow back on Theros. These people took the survivors in, fed them, and nursed them back to health.
During his weeks of recovery, Derethil studied the strange people, who called themselves the Uvara, the People of the Great Abyss. They lived curious lives. Unlike the people in Roshar—who constantly argue—the Uvara always seemed to agree. From childhood, there were no questions. Each and every person went about his duty.
One day, while Derethil and his men were sparring to regain strength, a young serving girl brought them refreshment. She tripped on an uneven stone, dropping the goblets to the floor and shattering them. In a flash, the other Uvara descended on the hapless child and slaughtered her in a brutal way. Derethil and his men were so stunned that by the time they regained their wits, the child was dead. Angry, Derethil demanded to know the cause of the unjustified murder. One of the other natives explained. ‘Our emperor will not suffer failure.’
As Derethil began to pay more attention, he saw other murders. These Uvara, these People of the Great Abyss, were prone to astonishing cruelty. If one of their members did something wrong—something the slightest bit untoward or unfavorable—the others would slaughter him or her. Each time he asked, Derethil’s caretaker gave him the same answer. ‘Our emperor will not suffer failure.’
The emperor, Derethil discovered, resided in the tower on the eastern coast of the largest island among the Uvara. Derethil determined that he needed to confront this cruel emperor. What kind of monster would demand that such an obviously peaceful people kill so often and so terribly? Derethil gathered his sailors, a heroic group, and they armed themselves. The Uvara did not try to stop them, though they watched with fright as the strangers stormed the emperor’s tower.
Derethil and his men came out of the tower a short time later, carrying a desiccated corpse in fine robes and jewelry. ‘This is your emperor?’ Derethil demanded. ‘We found him in the top room, alone.’ It appeared that the man had been dead for years, but nobody had dared enter his tower. They were too frightened of him.
When he showed the Uvara the dead body, they began to wail and weep. The entire island was cast into chaos, as the Uvara began to burn homes, riot, or fall to their knees in torment. Amazed and confused, Derethil and his men stormed the Uvara shipyards, where the Wandersail was being repaired. Their guide and caretaker joined them, and she begged to accompany them in their escape. So it was that Nafti joined the crew.
Derethil and his men set sail, and though the winds were still, they rode the Wandersail around the whirlpool, using the momentum to spin them out and away from the islands. Long after they left, they could see the smoke rising from the ostensibly peaceful lands. They gathered on the deck, watching, and Derethil asked Nafti the reason for the terrible riots.
Holding a blanket around herself, staring with haunted eyes at her lands, she replied, ‘Do you not see, Traveling One? If the emperor is dead, and has been all these years, then the murders we committed are not his responsibility. They are our own.’