I don't like how Sithis is some "non-living" things, because it is something, therefore can't be nothing. Just read the Monomyth you guys. In fact, here's the two paragraphs on Sithis and Anuiel from the Monomyth,
All Tamrielic religions begin the same. Man or mer, things begin with the dualism of Anu and His Other. These twin forces go by many names: Anu-Padomay, Anuiel-Sithis, Ak-El, Satak-Akel, Is-Is Not. Anuiel is the Everlasting Ineffable Light, Sithis is the Corrupting Inexpressible Action. In the middle is the Gray Maybe ('Nirn' in the Ehlnofex).
In most cultures, Anuiel is honored for his part of the interplay that creates the world, but Sithis is held in highest esteem because he's the one that causes the reaction. Sithis is thus the Original Creator, an entity who intrinsically causes change without design. Even the hist acknowledge this being.
Anuiel is also perceived of as Order, opposed to the Sithis-Chaos. Perhaps it is easier for mortals to envision change than perfect stasis, for often Anuiel is relegated to the mythic background of Sithis' fancies. In Yokudan folk-tales, which are among the most vivid in the world, Satak is only referred to a handful of times, as "the Hum"; he is a force so prevalent as to be not really there at all.
No where is he described as "non-living", only an opposite.