Safira Island is a world that works in 4-dimensions: height, width, depth, and spirit. The first three work exactly the same as ours does, defining an objects mass and volume, but the fourth is a bit more peculiar.
This fourth dimension, commonly referred to as the spirit-dimension, is said to be the realm in which gods dwell. While Safirans are not designed to exist in the spirit-dimension, their gods can, wafting in-between the planes of the mortal- and spirit-dimensions and altering them to their will. But while Safirans are unable to exist, or even see into the spirit-dimension, they are still able to sense it. For aqualoxes, their whiskers detect the links in the planes; for Terradins, their fractures are able to sense surges of energy; and the list goes on. These senses are what gives Safirans the ability to call forth elements from the spirit-dimension,.
And this is where Safiran magic hails from: calling your essence from the fourth dimension into the moral three. Essence defines a Safiran's magical prowess, and can be summarized as the amount of space they take up on the plane (similar to weight in the three dimensions). This can be changed with training, and the world has adopted a similar ideology to dieting in order to increase one’s spiritual breadth.
What happens when something from the spirit-dimension travels through the mortal-dimensions? Here's a video clip from The Action Lab that shows what a fourth-dimension would look like to three-dimensional beings, although you can watch it here for the full context!