Magic element (魔素 Maso, localized as seithr) is a substance that covers the planet. It cannot be tasted, smelled, or seen. However, in thick clumps it can be seen, and it looks like a black fog. The element can be categorized as a Particle Type Program (粒子型プログラム Ryūshi-gata Puroguramu), and it's unknown how and what creates it. The Boundary is filled with the magic element, and the Kilns are connected to it.
After the appearance of the Black Beast, the humanity has learned about the element. For the sake of victory over the Beast, Nine of the Six Heroes tried to teach people the art of sorcery, which is easier to perform than magic, and uses the magic element. However, people were not able to use it, so the Magic Formula, the fusion of magic and science, has been invented. When one uses Magic Formula, they draw the element out of the environment to power it, but there is only so much magic element in a given area. If one were to use up all of this element, they would have to wait a while for it to replenish. Some people can perform Magic Formula with less magic element than others.
In small doses, magic element is harmless to humans, and even has favorable effects on the world, as in the deeps of First Area, the element leaking from the Kiln was neutralizing radiation and other harmful substances, clearing the air of any pollution. In larger quantities, it can carry very detrimental effects; one can become addicted and their body will deteriorate. After the Great Dark War, a lot of humans and animals became tainted with the magic element and died off, save for the Kaka tribe. Humans were forced to move to high-altitude areas and create cities there. This is where the Hierarchical Cities come from.
It is believed that all living things are made of the magic element and humans can even be broken down to it either by the Soul Eater or when Unions progress to Phase 6.
During the course of BlazBlue: Chronophantasma, Bang Shishigami activated the Kushinada's Lynchpin, and the world has been depleted of the magic element. After the ending of BlazBlue: Centralfiction story, the magic element has returned to the world as it was before.
- The "magic element" is localized as "seithr" – it's derived from "seiðr", a type of sorcery which was practiced in Norse society during the Late Scandinavian Iron Age