Skraws are the Umbrielians responsible for tending and harvesting the sump. They take care of the growing worms that grow into Umbrielians. They breathe some vapors for breathing underwater, which damages their health severely. They cough very often, and they have a very short life. When they are not working in the sump they rest at the skraw warrens.[UL 1]
When Mere-Glim arrived at Umbriel he was assigned to the sump, due to his natural diving ability. When he knew about the vapors, he encouraged the other skraws to rebel against his superiors. He secretly organized a secret rebellion to sabotage Umbriel. In addition, they served as messengers between Annaïg and Mere-Glim.
The kitchens finally discovered that the skraws were responsible for the sabotage. Lord Umbriel ordered Annaïg to kill Mere-Glim, and the skraws were hardly punished. They were planned to be replaced by Argonian shaped Umbrielians, who would be able to breathe underwater and dive faster.[UL 2]
After the Ingenium was destroyed and Umbriel returned to the Oblivion plane of the Hist, the skraws and other Umbrielians left the flying city to find their livings in the lush world around them.[UL 3]