Æther is a thick, viscous liquid produced by Birds of Paradise. It is corporeal refined magic, and as such is incredibly powerful and dangerous to use. Due to its hallucinogenic and addictive properties, as well as its volatile nature, it is banned in most nations around the world. The international æther trade is considered the largest and most lucrative illegal industry in the modern age.
There are hundreds of different species of Birds of Paradise, nearly one for each island; the æther produced by each is different. The magical properties are more or less uniform across all types, but the potency depends on how close the island is to the center of the island cluster, with the strongest being that produced on Vortex. The color of each type differs as well, matching the most prominent color on the species that produces it. There is some speculation that these colors also correspond to schools of magic that benefit most strongly from it, but there has been little research and the results have been inconclusive. Nevertheless, some specialist mages will forgo potency in æther to buy specific colors.