The Immortal Fae by Odwald Bynothas
Fae do age, but only subtly, representing what would be the passage from youth to late-middle-age in a Young Race like humans. In exceptional cases, Fae may have life spans long enough to achieve an appearance of old age similar to human old age. The only obvious physical signs of this aging are in graying and silvering of the hair and tightening of the skin around the eyes, nose, and mouth.
Fae may suffer death from natural causes like aging or disease, or may suffer violent deaths. The Fae refer to their particular form of death as "passing," because though the Fae loses his body after his demise, his individual magical essence persists, moving on into the powerful flow of magic known as the Great Cycle. After passing into the Great Cycle, the physical body of the Fae returns to nature, just as with bodies of the Young Races.
Life spans for Fae are not determined so much by the passage of years, as for Young Races like humans, but the Fate of each individual Fae. Fae do not understand the notion of 'free will'. They imagine that the regeneration and subsequent passing of any individual Fae, and the sequence of hours, days and events in between, are pre-ordained and magically inscribed in the ongoing twists of their collective Telling.