Was a Ñoldorin prince, and the last in the line of the House of Fëanor, who lived in Middle-earth. He was a ruler of Eregion in the Second Age, and a master smith. He is remembered primarily for his creation of the three greatest Elven Rings of Power: Vilya, Narya, and Nenya.
Celebrimbor was the son of Curufin, who was the fifth son of Fëanor (son of Finwë and his first wife Miriel) and Nerdanel. During the First Age, he lived with his father in Nargothrond, but he took no part in the deeds of Curufin and Celegorm regarding Lúthien, Beren, and Finrod. He repudiated his father Curufin's deeds and did not follow his father and uncle when they were expelled from Nargothrond.
Celebrimbor settled in Eregion in the Second Age and started dealing with the dwarves of the realm of Khazad-dûm. In SA 1500, Sauron, calling himself Annatar ("Lord of Gifts"), befriended the Ñoldor of Eregion. He claimed to be an emissary of the Valar, especially Aule, and instructed them in the art of ring-making. Celebrimbor distrusted him, but the smiths of Eregion were deceived. Under the guidance and instruction of Sauron, the smiths openly made rings to learn the craft, but unknown to them the craft taught by Sauron incorporated a binding magic into the rings.
In secret, Sauron forged the One Ring, a master ring that would rule all the lesser rings, to enable him to rule Middle-earth via its influence over those who used the other rings. When Sauron placed the One Ring on his finger, claiming dominance over all the Rings of Power and their bearers, the elves knew his true identity and intentions. Celebrimbor and the elves of Eregion defied Sauron by withholding the other rings from him. The greatest of the rings (aside from the One Ring) were created by Celebrimbor himself, and these were never touched by Sauron and thus were uncorrupted by him, although they were still subject to the One Ring. These were the three Rings of the Elves, the fairest of the Rings of Power. Celebrimbor named them Vilya, Narya, and Nenya after the principal Middle-earth elements of air, fire and water, respectively. He sent the three rings away for safekeeping: Vilya and Narya to Gil-galad in Lindon; and Nenya to Galadriel in Lórien.
Sauron retaliated by attacking Eregion, laying waste to the realm. Celebrimbor was captured in the chaos and was forced, under torture, to disclose where the lesser rings were, but he would not reveal the whereabouts of the three greatest of them that he had sent away for safekeeping. Celebrimbor died from his torment; his body was shot with arrows and hung upon a pole, and was later paraded as a banner as Sauron attacked the elves. He was the last direct descendant of the line of Fëanor, save perhaps for his father's brother Maglor, whose fate is unknown and is said by some legends to still wander the shores of the Sea.
Unlike both his father and his grandfather, Celebrimbor was portrayed as being both selfless and kind, and was neither prideful nor covetous of that which he created. He was described to have an "almost Dwarvish obsession with crafts"; he became a famous artificer and smith in both Gondolin and Eregion. His love for crafts took him to Eregion, where he was introduced to a precious metal and called it Mithril. Mithril was mined by Dwarves in their nearby Mine Realm of Khazad-dum, later renamed Moria. Great friendship with the Dwarves of Moria developed, skills and secrets were shared between the two peoples for many years via The High Road which was built between the two realms. But a long period of peace would not last, for upon realizing the trap which Sauron had devised for him, Celebrimbor was filled with anxiety and fear for his people, and was later described as the heroic defender of Eregion.