The Aen Elle are
elves that exist on another world, or another plane of existence. They do not normally live on the Continent of the Witcher series and are otherworldly. Aside from that at large they don't appear to be that different from the Aen Seidhe.
Aen Elle In Game
Major Story Spoilers
The riders of the Wild Hunt are actually Aen Elle from a different world than the one in which The Witcher takes place. They appear as specters to those that witness them, due to how time distorts between planes and realms, it is difficult to tell how long they have been around or how old their members would have to be. Those that are taken may reappear in our world decades later while having spent only a month within the world of the Wild Hunt.
