Light
Within every living or nonliving being on Luxos, there is light. It is even present in the air. A nebulous compound and force summarized as "life force" or "magical entity," its presence is what everything in the world has in common.
Light itself is well-understood on a foundational level. It is not actually a single particle, but a collective of nine aspects (or "elements"). Living organisms primarily have one aspect of light flowing within them, which also correlates to the aspect that they can manipulate through magic.
While the aspect of light within a person correlates to the aspect they can wield with magic, there is evidence to suggest that people also carry minute traces of other aspects with them.
The atmosphere in Luxos is filled with "pure" light, a homogenous blend of every aspect. This presence allows for magic to be cast even when there is nothing present—water can be extracted where there are no rivers, and fire ignited without embers or kindling.
Though it is constantly flowing, atmospheric light will occasionally pool in certain places. For example, a dense cluster of light forms in South Pyrus once every ten years. This phenomenon amplifies the precognitive abilities of House Infiaco members, allowing them to see much further into the future than usual.