Indeed, the reason these two elements get much attention when it comes to design is because they cover many mystical elements that we can't actually measure. Aether is not only what divine realms are made of, but also the unmeasurable media through which energies flow between dimensions (which we can't measure yet, either) and stars. Darkness often gets a mystical treatment too, in accordance with cults, demons, and so on. It's no coincidence the two elements have a lot of synergy.
Of course, when it comes to theft and/or misdirection, this could also fit in Entropy.
