Aether was once described to Arthur Leywin by Myre like this; Mana is a liquid in a cup, changing to fit whatever shape, always moving and flexible. In this metaphor, Aether is the cup itself, stiff, unchanging without lots of force. It is solid, it will never change itself without some outside force.
Aether is originally known to have 3 different types. Those are Spatium, or space aether, Vivum, or the aether of life, and Aevum, time aether.
This is thrown off course once Arthur creates his aether core. He is shown manipulating aether, something previously thought impossible, and using it like mana. Upon discovering his new power, Arthur learns that the race of ancient mages, the djinn, who created the portals and the underground city in Dicathen, could manipulate the aether as they wished.
The aether type that controls the existing space. This is the aether that is the most seen throughout the total of the novel and webcomic. It’s power goes from the teleportation up to folding space itself to the users will.
Some known power and abilities relating of the Spatium are:
Teleportation Portals: Manifested, old arcs scattered around the three continents, these arcs have helped both Dicathen and Alacrya in their creation of cities and civilization. It is known that the portals found in the deepest parts of the dungeons have the ability to transport beings between the continents.
God Step: An ability named by Arthur as an evolution to burst step. After the aether crystal containing the memories of the djinn gave a god-rune to him, Arthur manifested its power as God Step. It’s power is to create a teleportation-like movement where Arthur can move through incredible distances within an instant.
It has been seen that the three bases of the beast-will of Sylvia is capable of manipulating Spatium in addition to Aevum. This is shown by creating a portal to the secret city of the djinn and folding space for people to get near to it.
The aether type that controls the time of the world. This type of aether is natural for both Kezess Indrath and Sylvia, as shown in her 3 phases of will when Arthur uses them. An artifact that is known to possess this kind of aether is the mana box, the crystal that the djinn gave to Arthur as an extra reward.
Aroa’s Requiem: A God Rune that Arthur received from the djinn’s crystal, Aroa’s Requiem allows him to reverse time on inorganic objects. It appears that objects affected by aether can resist this ability, possibly due to Arthur’s lack of experience using it.
Also known as the aether of existence, this aether was previously thought to only control life. Later, in the novel, the aether of existence (life) consists of actually four types or branches of aether: Life, Death, Creation, and Destruction.
Rune of Destruction: An ability unlocked by Arthur when trying to escape one of the four ancient ruins. By unlocking it, it manifests as Arthur's greater thought of destruction, fire. It generates amethyst-flames that devastate everything on its path. Unfortunately, it’s side effect is to make Arthur go insane; it becomes worse every time he uses it.
It is actually possessed by Regis, who cannot control it to the fullest for the moment.