Aether is the essential magical force that permeates the world. Aether is used to fuel superhuman feats, whether in terms of curses or techniques, and is present in every living thing. Aether makes material and even people more hardy and resilient, allowing them to survive things that we normally wouldn't think a person could survive and not easily become sick.

Techniques are ways to manipulate the body using aether to perform superhuman feats. When a person uses techniques, they  draw in aether through their lungs and then utilize the aether to make their body move faster or hit harder than they could have otherwise. Techniques vary across people, but the Military Police have a formalized version called the Five Paths.

Curses exist where the suffering is greatest. Curses are alterations to human anatomy that allow humans to manipulate their body or environment in ways that are normally possible through techniques. Each curse is individual and unique, though some may be similar in broad strokes. The true nature of curses and their origins are unknown to the wider world.

The real world of the Erth. The Real is the plane that all things exist on, and is where everything that happens in the world actually happens. The Real can be a strange place, but in the end, it operates mostly like the world the reader is familiar with.

The Surreal is the realm of aether, and the origin of strange things. The Surreal is where curses and techniques find their power as well as their ability to bend the rules of the Real. The Surreal has many odd creatures that inhabit it, though they are invisible to the Real the vast majority of the time.

The Outside is the world beyond the Real and the Surreal. It exists as an empty void that is visible from the interior of island cores. The Outside has no known occupants and appears to be an inky black substance.

Ironwood is a substance taken from a specific type of tree that has the properties of metal. While it isn't metal, it is magnetic and has a hard surface. Ironwood is sold across the Erth by the Green Dragon Company.

A substance that has the ability to eat aether from the environment around it. Aether-eating metal has no known place of origin and has mainly seen use by the Military Police or through the artificial creation by an island core.