Twin Swords of Fury

The Twin Swords are the fragments of the Fume Greatsword reforged and the sword was split by the master blacksmith Headrig using the Silver Gauntlets. As a pair, they are legendary weapons wielded by Cas. Thanks to Cas's tremendous strength, he is able to wield the heavy weapons effectively.

History
Not much is known about the history of the swords. While still together as the Fume Greatsword, Cas received them as a fulfillment of Link's wish to the Djinn set free in the Cave of Wonders.

Powers
The weapons are mighty in that they are much heavier than average longswords and thus hit much harder. They weapons hit more like sharp clubs than swords. As they are technically still one item, separating them essentially turns them into fancy pieces of rubble that are ineffective as weapons. As the current wielder is still unable to unlock the weapon's full potential, the abilities of the swords has yet to be unveiled.