Celebrimbor:

One of the Noldorin Elves, and lord of the Elven realm of Hollin, also known as Eregion, on the western side of the Misty Mountains, Celebrimbor was the grandson of Fëanor. He drew the symbols on the western gate of Khazad Dum. Fooled by Sauron in the guise of Annatar, he helped to forge the Rings of Power, both greater and lesser. On his own, Celebrimbor created the Three, the Elven Rings. He was killed by Sauron when Eregion was overrun by the Dark Lord's armies, after discovering the forging of the Ruling Ring when Sauron placed it upon his finger. However, he was able to hide the Three from him long enough to pass them to their guardians.