Adamantine butterfly swords

A pair of butterfly swords forged from adamantine used by the drow. You can make two attacks with these swords but only one sheath is necessary to store these swords. Since the swords are made of adamantine, they are practically unbreakable and if you roll for attack you can roll three d20s and divide the result by two. This sword deals 2d20 slashing damage for each sword, but you don’t have to roll to hit twice.

Notes: Damage: Slashing, drow