Machina

Machina is a forbidden branch of magic which directly involves the infusion of aetherial energy into mechanical constructs, the term may also refer to the infused constructs themselves. During the height of the Exodian Era, humanity used machina in almost every area of their life. Humanity's excessive use of machina led to the rise of Exodia, the greatest human city to have ever been built. There were other, less notable machina cities such as Jeth, and Laicura. While pure aetherial constructs are able to emulate some of the utility that machina possessed, the latter is far more powerful and does not suffer the drawbacks of the former. It is theorized that exodian machina drew massive amounts of aetherial energy from an unknown source, a key principle of machina that has been lost after the collapse of exodian society. Machina were believed to be self-sustaining, and unlike pure aetherial constructs they could operate indefinitely without static resistance. Humanity considers machina to be forbidden, anyone who attempts to learn the practice is executed without question. The elves have dabbled into machina in the past, but without knowledge of the mysterious power source that machina derive their power from, they dropped the field in pursuit of pure aetherial magic instead.