Amber: Something Wicked
Unaging or extremely long lived, hard to kill people with bodies and, nearly always, the potential to world-walk and high aptitude for magic and other powers. (As opposed to Spirits, Elementals — spirits bound loosely to matter, the Dead in the Otherworld and Mortals.)
Makers and nearly all the natives of the Otherworld are Immortals. Fae — ‘noble’ Fae — are descended from Otherworlders who lived in the Middle World prior to its breaking and re-Creation. Most Fae have a strong Elemental Affinity of some sort. Rebman royals and high nobles are Fae. If Fae breed with mortals the extreme longevity and powers are attenuated.
Successfully walking a Pattern makes you and your genome solidly Immortal.