Ethereal

What is Ethereal Magic?
Ru'aun, the Middle Realm (otherwise known as the Divine Realm), and the Other Realm all possess a natural magic to them. Divine Gods, Elves, Draugr, and Demon all have the ability to access this naturally, and are born with the talent to do so.

Even though these races can access the natural magic of the realm, they still must be taught and practice it in order to gain access to it. Each race does it a little differently, and Draugr are the most keen with picking it up. While, Elves are the only ones able to access the forbidden magic.

Ethereal Magic is also just called magicks by some.

Forbidden Magicks
Resurrection - Able to bring back the dead to the living. This costs the user to take part of their life, however, cutting it down by half. It’s a forbidden art.

Realm hopping - It is said the Divine Gods each have a realm that belongs only to them. Elves are able to reach it, but it takes a great amount of power and is forbidden due to what is needed to actually use this.

Barrier breaking - Performing this allows a magical barrier to be broken. Depending on what kind of barrier and how powerful the magic is, it might take more people and more energy.

Time Turning - Only ever performed once by the Augur, but taught to the Yggdrasil Elves, to use this would allow the user to turn back time by 5 minutes. The cost of this is hard enough on a Divine God, and for an elf to use it they would need to get a group of 5 to sacrifice themselves to turn back that time.

Affinities
An Affinity is simply a better term for magical elements that can be harnessed through Ethereal Magic and even be put into a weapon to give it a certain "Affinity".
 * Putting an Affinity in a weapon helps the user channel that specific Affinity especially if its someone like a Human who can't naturally channel magicks.