~Immortality of Faeries~
St. Columcille told the fairies they would be annihilated on Doomsday. St. Patrick was more generous and assured them they would not achieve Paradise until the Last Day. However, he did not mention whether at that time they would be granted permanent residence; since their bodies are not of substantial matter, they would be incapable of participating in the general resurrection of the body. The fallen-angel advocates, on the whole, argue for the destruction of the sídhe. Since fairies are not actually good creatures, they must, by inverse argument, be somewhat tainted, and hence not suited for the continuing joys of heaven. Some contend that fairies hold a grudge against humankind because humans usurped their rightful immortal seats. Humankind being allowed to polpulate the angel-depleted Heaven left no room for the irresolute fallen ones, and so they have sought revenge against our race by numorous spiteful acts.
Yet there is no doubt that fairies are immortal. Fairies are gods; and doctrine is too blunt a weapon to destroy them. An irish fairy of one faction may blithely cudgel a fairy of another, and the latter will seemingly be no worse for the blow. Fairies know neither disease nor death; their immaterial bodies are not subject to decay. Nothing physical can prevent them from living forever. And if they thought for a moment that God would not grant them on that last day their rightful place in Heaven, they
would destroy this world and all that is in it. God and the fairies have a better understanding of one another than mortals are inclined to believe.
Source: Carolyn White "A History of Irish Fairies"