Sword of Kings (SF)

From the introduction: It has many names, from many worlds. Caelfydch. Central Control Device. Dakana. Haelgard. Ruleware. Worldbinder. The Eternal Crown. Regardless of the exact name used, most researchers agree on its conceptual role. It is the Sword of Kings. A runic weapon that contains within it the rune of rulership, smelted down through means beyond mortal ken, alloyed with metals from the edges of space and science from civilizations dead a billion years, and turned into a symbol of royalty as much as a weapon for defeating foes.