User blog comment:ErnestoHF/How ends Middle earth?/@comment-26322120-20160521171301

"Thus spoke Mandos in prophecy, when the Valar sat in judgement in Valinor and the rumour of his word was whispered among all the Elves of the West. When the world is old and the Powers grow weary, then Morgoth, seeing that the guard sleepeth, shall come back through the Door of the Night out of the Timeless Void; and he shall blacken the Sun and the Moon. But Eärendil shall descend upon him as a white and searing flame and drive him from the airs. Then shall the Last Battle be gathered on the fields of Valinor. In that day, Tulkas shall strive with Morgoth, and on his right hand shall be Eönwë, and on his left Túrin Turambar, son of Húrin, returning from the Doom of Men at the ending of the world; and the black sword of Túrin shall deal unto Morgoth his death and final end; and so shall the Children of Húrin and all fallen Men be avenged. Thereafter shall Earth be broken and remade, and the Silmarils shall be recovered out of Air and Earth and Sea; for Eärendil shall descend and surrender that flame which he hath had in keeping. Then Fëanor will break them and with their fire Yavanna will rekindle the Two Trees, and a great light shall come forth. And the mountains of Valinor shall be levelled, so that the light shall go out over all the world. In that light the Valar will grow young again, and the Elves awake and all their dead arise, and the purpose of Ilúvatar be fulfilled concerning them. But of Men in that day the prophecy of Mandos doth not speak, and no Man it names, save Túrin only, and to him a place is given among the sons of the Valar." - The Later Quenta Silmarillion (History of Middle-earth, volume 11).

~The One Wiki, Dagor Dagorath.