Being a fantasy world, Kenah has the customary set of magical elements, but they're a little different from the classical fire-water-wind-earth set. One of the biggest themes of the story is balance, and this is reflected in the magic intrinsic to its makeup.
The planet is full of raw magical energy, or mana, and it can take form in many ways. One of them is through elemental or planetary magic. There are six elements on Kenah: heat, light, energy, time, weight, and movement. Each one is broken up into two aspects: one for presence and one for absence. Unlike in real Earth science where, for example, darkness is just an absence of light, the aspect of Skadis is in and of itself a force, impenetrable by regular, non-magical light.
It's important that the planetary aspects be in equilibrium as much as possible within the planet overall, but it's common to find pockets of one aspect building in an area, called Cores: for example, a volcano is a natural place an Ignia Core may form, and you might find a forest unnaturally dark because of a Skadis Core at its heart. It's a bit of a chicken-and-egg game as to which came first, the mana or the ambience.
The designs of the symbols took a lot of iteration to get to a point where I was somewhat satisfied with them. (I'm still not 100% happy, but maybe I never will be, and you gotta stop at some point.) For each set, the presence and absence had to make some reference to what they were embodying, mirror/reference each other in some way, and be able to combine into a single symbol as well. A lot of them, heat especially, used to be more organic looking, but it was harder to fit the criteria that way. eventually i decided on the geometric stuff because, well, that's my jam.
some old development doodles:

here you can see me struggling with Movement, and making things not look like pokeballs and peace signs and tripods.