Eladrin are a type of fey native to Thelanis that resemble fantastical elves. As fey, they are influenced by the stories they are part of, which alter their appearances and personalities. Many eladrin have the innate ability to teleport short distances, and the more powerful eladrin are also able to use the fey magic of Glamour to alter their appearance. Eladrin are immortal in Thelanis, and will reform within their story if destroyed.
Modern elves are descended from Eladrin, forcefully brought to Eberron after the sacking of Shae Tirias Tolai at the hands of the Giants of Xen'drik. Prolonged exposure to the material plane causes an eladrin to lose their immortality, and the elves became mortal long ago.