J. R. R. Tolkien's The Lord of the Rings is full of characters from a variety of different species, and Aragorn heads up the story's human contingent; but what happens to the returned king after the story ends? When Frodo first meets Aragorn, he's masquerading as a simple ranger and going by the name of Strider. Presenting himself as a man of the wild who befriended Gandalf on his travels, Strider knows of Middle-earth's plight and is willing to help the Hobbits on their mission to destroy the Ring.
Gradually, it becomes clear that Aragorn is a far more significant figure that he initially let on. His girlfriend is an elf for starters, but he's also strong enough to repel the Nazgûl, wise enough to resist the lure of the Ring and noble enough to have a prominent voice during the Council of Elrond. Ultimately, Aragorn is revealed to be the descendant of King Isildur, hidden away in Rivendell as a child to protect him from those who would seek to destroy the line of kings. After Sauron's defeat and the Ring's destruction, Aragorn takes his rightful position and ascends to the throne, enjoying a celebratory coronation ceremony in Gondor at the end of The Return of the King.
Of all the Fellowship, Aragorn's 'happily ever after' is perhaps the sweetest, as he avenges his ancestors, restores the royal line and marries the love of his life, but his story doesn't end there. Tolkien is renowned for detailed writings and appendices that expand the world and lore of The Lord of the Rings and Aragorn's story is continued with a short but meaningful epilogue of sorts.
Following the events of The Return of the King, Aragorn's reign predictably heralds in a new era of prosperity for Gordor and the peoples of Middle-earth. The former ranger is crowned King Elessar, and his line of descendants dubbed the House of Telcontar, the latter term deriving from the word "Strider" in a subtle nod to Aragorn's former life. Despite the downfall of Sauron, there is still plenty of work to be done to return the land to its rightful state.
Aragorn's foremost achievement as king was the establishing of the Reunited Kingdom; a joining of Gondor and Arnor (in which lies the Shire, Bree, etc.) and the reunification of an ancient kingdom of men that had been split up many centuries prior. With the military might of the Reunited Kingdom, Aragorn set about reclaiming lands that had fallen into ruin during the War of the Ring or before, such as Harondor in southern Gondor, the Rhovanion region Sauron once took residence in and Umbar, which had fought against Gondor in the War of the Ring.
With these campaigns, Aragorn managed to return Gondor to its former glory, and clean up the remaining murk and darkness that had been left by Sauron's influence. The Reunited Kingdom prospered as a result and the friendly relations between men, elves and dwarves that had been forged at the end of the Third Age were maintained, as Aragorn led a mammoth rebuilding of the lands destroyed by conflict.
Aragorn lived happily with Arwen for 120 years following the end of The Return of the King and the couple had one male child, Eldarion, as well as an unspecified amount of unnamed daughters (gender equality obviously wasn't thriving in Middle-earth). When Aragorn began to sense his time was drawing near, the noble king chose to take command of his own end. Not wishing to "wait until I wither and fall from my high seat unmanned and witless," Aragorn took to the House of Kings in Minas Tirith, where Gondor's past rulers had been laid to rest. Here, Aragorn said his farewells, handed over his crown and scepter to Eldarion and peacefully drifted into an eternal sleep, remaining forever in a state of grace for others to look upon him in wonder.
Arwen, who had become a mere mortal after Elrond left Middle-earth, was left forever grayed by her husband's death, and took to the elvish realm of Lothlórien, where she saw out the remainder of her days. Only after both of his parents had passed away did Eldarion take the title of King.
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