The Fables are the magical people and creatures originally from the equally magical Homelands. Talking animals, humans, fairies, trolls, ogres, goblins, dwarves, witches, giants, dragons, and other creatures are but a sample of all the kinds of fables that exist. The lives and exploits of many of these creatures had been leaked into the conciousness of various mundy authors and therefore their stories, albeit deformed, have been told for centuries in the Mundane World. Although all denizens of the homelands are considered fables, not all fables develop certain traits that only some of them seem to possess. Based on the popularity of their respective stories, Fables gain power that manifests mainly in their endurance against dying. By their very nature, many fables are long living creatures, but a popular fable can stop aging altogether and develop a healing factor that would help them survive otherwise fatal injures.
However, this doesn't mean that they are immortal. A fable, no matter how popular, can be killed. Once dead, they could potentially come back from the dead, provided their story be popular enough, but most likely the role they left could be occupied by another fable instead.