The Spiral Skein is the realm of Oblivion created and ruled over by Mephala, the Daedric Prince of Lies. Some portions of the realm resemble a dark, sprawling cavern with a high ceiling, dotted with luminescent mushrooms. Spiders, hoarvors and all manner of crawling creature inhabit the plane, and tall buildings with arches and spires dot the landscape. Crystals of deep red hues jut from the cliffs, ceilings and walls in geometric clusters comprised of prism-like shapes.
The Spiral Skein is metaphysically constructed in a similar manner to Nirn. At the center is the Tower, known only as the Pillar Palace of Mephala, since its true name is too awful to be uttered. The Spokes are called the Eight Strands of the Skein, and the spaces in between are each devoted to a different sin. The first is a cavern devoted to lies, filled with pedestals pretending to hold up the sky. The second is made up of cramped chambers representing envy, while the third is maggot-filled grottoes filled with seductive light. The fourth contains eternally dark tunnels of fear; the fifth, a place of betrayal; the sixth, an arena of murder. The seventh space is home to arcades of avarice and appetite, containing all things mortals would kill or die for, while the eighth is a flaming skein of fury, representing the death that comes to all mortals.
Mephala's realms are said to be numerous and obscured, collected together by vast strands of magical ghostweb. All of them are devoted to her spheres of sex and secret murder.[UOL 1]
The Spiral Skein has diverse flora that thrives in the darkness and most have a bioluminescence. The Glowbush, and Midnight cap, Nettlecap, and Scarlet Sawleaf, And Shadowpalm are native to the realm. The Bat bloom is a type of plant that grows naturally on Vvardenfell in the Bitter Coast, Ascadian Isles, and Azura's Coast regions in shady areas but seemed to have made their way into the Spiral Skein.
Aside from spiderkith and hoarvor daedra, skein spiders, scorpions, wasps and beetles have taken up residence there. two coral varieties also grow inside the spiral skein. The Brittle-Vein coral thrives on the remains of people who fell victim to the spiders from the realm, and the Spiral Skein Elkhorn gives off a welcoming bioluminescence that the spiders have used to lure victims into their webs.
Note: the following references are not from official sources. They are included to provide a rounder background to this article, but may not reflect established lore.