The blade of this sword is 3 feet in length, only 1.5 inches wide and has a drain in the centre to allow blood to drain down. The metal is bright like silver but strong like steel and does not chip, most probably it is some kind of alloy of half a dozen rare metals of which adamantium and mithril are two likely candidates. The hit is forged of a darker metal whose composition cannot be guessed at; the handle is a snake head while the blade itself appears to sprout from amid its coiled body. The sword is called Ist and its makers, along with the secrets of its construction, are a thousand years dead.
Most likely this blade was once one of a pair of weapons, as it is of a weight and balance consistent with that preferred by warriors who fight with a blade in each hand, though to have a second blade manufactured now to fit these exacting specifications would require the work of a master smith and is almost certainly beyond the ability of even the most skilled of humans.
In combat Ist functions as a long sword +2. Once per day the sword can be used to deliver a more powerful attack. The wielder must declare they are using this power before rolling to hit. If the hit is successful then damage is doubled and if the score was a critical hit then base damage rolled is multiplied by 4.
If the partner to this weapon could be found, or is a new partner could be made – which would be at enormous expense – then both blades will function as +3 to hit and damage, though they will only hit creatures which could normally be struck by weapons of +2 or lesser enchantment.
(This item is from the world of Saas)