Aetherium is a term for both a substance and a supernatural element found in Magnaorbis. It is, arguably, connected with the Maelstrom and is believed to itself be a part of the power of divine beings. It is unknown whether or not it can be used by non-divine mortals beyond Magnaorbis, but within the construct, as a result of the components of Magnaorbis, even mundane individuals can, through a combination of genetic luck and learned skill, use Aetherium Powers. Nevertheless, in all but the most aetherically inclined, its use is limited to short bursts or minor actions when used in its non-substantial form. Substance Aetherium (as it is termed) is, however, a part more potent tool. It is believed that in the creation of Magnaorbis, Omorthan Sheol bound significant amounts of Aetherium to mundane minerals, ultimately creating Substance Aetherium. It is a widely held belief Non-Substantial Aetherium use is only possible as a result of the nearby presence of Substantial Aetherium on Magnaorbis. However, unbeknownst the the general population of Magnaorbis, the non-substantial use of Aetherium is in fact possible by mortals as a result of the lingering aetherium in the area created by the birth of Omorthan Sheol which has since then become a part of both the genetic sequences of Magnaorbis' inhabitants and their souls. To those in this small circle of knowledge, it is suspected that Omorthan Sheol's creation of Magnaorbis was not merely a societal experiment, but also an attempt at uncovering what would occur if mortals were exposed to raw aetherium over generations. While the aetherium influence is not capable of uplifting Magnaorbis' inhabitants to a divine or semi-divine status on its own, the powers conferred by it are indisputably more than most mortals elsewhere could hope to have, even if in the scale of things they are relatively minor.

Aethertech is technology created to harness Substantial Aetherium which, beyond minor bending capabilities by the most gifted Aetherium Users, is useless without such technology. While the confirmed discovery of Non-Substantial Aetherium Powers (after countless generations of unconfirmed oddities) was made in the reign of John I, ushering in the Third Era, aethertech itself, in spite of the soon thereafter discovered abundance of Substantial Aetherium, did not come of age until the reign of James VII. The advent of aethertech, in conjunction with the Steam Revolution, is credited as one of the most profound advancements ever achieved in all of Magnaorbis and itself signaled the beginning of the Fourth Era. With its mundane counterpart (which had and has a mutually beneficial relationship with aethertech (with an advent in one often being possible because of an advent in the other)), aethertech revolutionized the way of life in Magnaorbis, and played a crucial role in New Britannia's increasing dominance in the era.