Many legends existed about the life and deeds of Usul, both before and after the appearance of Paul Muad'dib.
In this version, Usul was still a boy when he decided to leave his sietch before his minha, the season of testing, as his mother reminded him. Nevertheless he left to the desert and as the sun was setting, he saw some little way off a castle made all of sand.
Inside the castle was a room, empty but for a table of sand on which stood a jug of liban and a bowl with some apricots and after he ate, he lay down to sleep. Then the voice of Alhen (Death), "Naib of All the Djinn" threatened him for entering his castle and eating his meal.
Usul replied: "Jild an havy ma tumal minn-u harakis" (Shoes are not made of the hide of a living animal). Then the marid laughed and grabbed Usul by his hair and threw him into a pit in the center of the castle.
Usul sat at the bottom of the pit and a small mouse appeared and told him "Ya mawla, argab aanina!". Its wife gave birth and its tribe would starve without it, so it asked Usul to throw it over the pit. As Usul did this, the mouse replied "Tija al-sadaqa" "The gift will return to the giver" and Usul passed the rest of the night alone.
The next morning, the jinn grabbed Usul from his hair and threw him in the desert.
Then a mouse introduced as Mixabbi and advised Usul to learn from it. The mouse began to sniff the wind and to watch the spray of sand from the dune tops. Τhe mouse burrowed then stopped as the sand drifted down. When the mouse found the shadow of the wind, where the burrow did not collapse, it tunneled deeper and curled up inside with its nose deep inside its fur.
The wind rose until before him there stood what seemed like a swirl of winds in the shape of a man, the Yellow Djinni Azfar who would eat Usul. Then following the mouse's example, he found the shadow of the wind on the lee side of a dune and crawled from place to place, testing the sand. When he found what the mouse had taught, he dug into the sand and scooped himself a burrow. Usul waited until the storm blew itself out.
Then Azfar told Usul that he won. If Usul ever became free, Azfar would do one service.
When Usul tried to reply, he foudn himself in a cavern. Then a mouse came, introduced as Rauhanin and showed him "peace": it hopped to the floor and crouched as if it were praying without moving no matter what Usul did. Thinking that the mouse was dead, put it on the floor again only to see it rise, shake itself, and run off as a distant rumble was heard until Usul's head rang.
It was Ahmar, the Red Djinni who would eat him. Usul thought he could bear no more of the loud beating, and fell to his knees, clutching his ears and grinding his teeth. Thinking of the mouse, he looked deeper and deeper inside of himself, for the small place where all is quiet. He looked and breathed from the center of his soul, and as he looked, he heard the drum less and less. Then he found the silent place, and rested there in reverence.
Then, a pebble had fallen on him and Ahmar replied weakly and distantly when Usul becomes his own master, the djinni would do him a service.
Usul found himself on an omnidirectional gray floor, stretching as far as he could see all round him, with a gray sky over all. Then a mouse came and introduced as Basbasiyah. It lept to the floor and began to wiggle its tail, hpping, jumping and dancing until Usul laughed.
A drop of water fallen on his face and through moans and sad noises, from a dask cloud caame a sorrowful voice. It was Abiad the White Djinni that would eat him. He saw his mother and sister sorrowful for missing him. Usul started crying and feeling very sad and alone until remembered the mouse. He started laughing and before he knew it, the gray land was alive with his mirth and the echoes answered his laugh with giggles and chuckles. Then Abiad said that once he would free himself, he would not forget that Usul bested him.
Usul again found himself in the pit. It was night and once again fell to sleep. The morning Alhen again grabbed him and said that since Usul escaped his donkeys, whether he would do something to gain his freedom. But Usul would not ask anything. Then the Djinn asked from Usul portyguls from a garden. Usul said he would do it "but only because it pleases me to get some portyguls myself".
He called Khala, folk of the air to show him the portyguls. After he ate, he took three for the djinn, and then boasted that the garden is unguarded and any outcast would enter. The djinns replied that they were imprisoned there because he could not reach their hearth by nightfall. Then Usul realized he could not return to the same way because he would fail to return in time.
To that purpose he marked where the sun rose and set a course straight and fast for Alhen's castle.
His path led him over a jagged rock wall, from which he looked at kaymus, dust sand, in the basin. He ran down the slope, until he felt no ground and fell in a pit filled with bar almeda and sunk until could not breathe. Then he called Azfar. Since Usul was not free, the djinn asked for one of the portyguls. The djinn then lifted Usul from his cloak. Then a mouse came and Usul boasted. But the mouse replied "You had a djinni to help you. If a hawk should snatch me from a scorpion, that does not make the scorpion my slave nor the hawk my ally."
As he crossed a low range of dunes. He stepped steadily across the salt basin, heading for a ridge of rock on the far side. When he came to the very middle of the place, he felt drum sand and this atambal would call a worm. The drum sand would give him firm footing, he knew, and he judged the distance to the rocks carefully. He then asked help from Ahmar. The djinn asked him for a portygul because he was not free, and with his drum he sped, luring the sandworm. Usul made his way to the rocks and sat down to catch his breath. Then a mouse came to whom Usul boasted but it replied "Make sure when you cross the desert you always have Ahmar's drum at your call and no worms will bother you."
Usul thought as he proceeded that while he had not beaten the uncaring earth nor the greedy worm, and he was thirsty. Usul lay flat on the desert sands, too weak to move. Two mice came and talked about him. They said that this boy was not Usul master of Dune because he is not his own master. Then he called Abiad, to weep and slake his thirst. Once more, the djinn noted that Usul is not free.
But Usul replied that he is free because it's to his will to bear or to bow, to endure or to submit, and the mightiest naib can say no more. If I were to die in chains, I will still have a freedom that no one can take from him.
The djinn again asked for a portygul as a reward but Usul said no, because he would eat it himself; he did not intend to return to Alhen.
Once he found himself in the pit with the djinn angry, since Usul broke his promise. But then, Usul gave him the portygul he still held. The djinn then realized it was bested and offered him anything, even the whole planet. Usul denied saying that the djinn "can give me nothing that I lack or cannot get for myself".
He took only a gift himself would give. A name: the name of his preceptors, whose teaching brought him through all troubles. The new name shall be called 'Mouse'.
It was the name given to Paul Atreides when he was given sanctuary with Sietch Tabr by its naib, Stilgar. Openly Paul was to be referred to as Muad'Dib. However, Usul was the private name used within the Sietch. It was to be the name his beloved Chani would use for him, and the last word she cried before she died giving birth to their children.
Stilgar gave Paul this name after witnessing him defeat one of their finest wariors, Jamis. It would appear that Stilgar saw a certain strength in the boy.