[Ainaserkewen]

If you want to read about the only existing writings by Tolkien on the fourth age, check out The peoples of Middle-Earth, from the History of Middle-Earth collection organised by Christopher Tolkien. Part of the special addition was "The New Shadow" in which a story unfolds about two Gondorians one hundred years after the war of the ring ended. They discuss the changes about the world, and how the younger one was part of a group of teenaged "orcs" causing trouble and now in a cult of secret dark worshipers. Aragorn has just recently died, by the way.