Orcrist, Thorin's sword(Lord of the Rings)

Forged by the Elves of Gondolin in the First Age, Orcrist was not just a prestigious weapon, but almost a character in its own right. Its name means "Goblin Slayer", a translation of the Goblin-cleaver and its Elvish runes betray its origin when Thorin discovers it in the troll cache, before Elrond identifies it.
In the films, the craftsmen have taken the detail a step further: the handle is shaped like a real dragon's tooth and bears the Sindarin inscription "NAGOL E-LYG", literally "Dragon's Tooth". This choice is based on the official material for collector's replicas, which even mention this engraving.
After the Battle of the Five Armies, Thranduil returns Thorin's sword and places it on his grave beneath the Lonely Mountain. There, Orcrist is supposed to glow in the dark if enemies approach Erebor. From a sword of conquest, it thus becomes the eternal guardian of the Kingdom beneath the Mountain.