Lostvayne

The Demon Sword, is a sacred treasure belonging to the Dragon's Sin of Wrath, Meliodas.

Appearance
Lostvayne takes on a form of a curved shortsword with the Dragon tattoo emblem into it with five holes on the sharp blade.

History
Entrusted to him by King Baltra, Lostvayne was in Meliodas' possession until 10 years ago when he sold it in order to raise money to open the Boar Hat. Merlin later bought it from a pawn shop in Camelot and kept hold of it until she returned it to Meliodas during Albion's attack on Camelot.

Current Arc
While saving Arthur from Albion's attack, Meliodas' sword which was a gift from Liz is broken, leaving him without a weapon. This prompts Merlin to return Lostvayne to him in order to combat the giant monster.

Abilities
Lostvayne seems to have a multiplying affect, turning one of Meliodas' strikes into several strikes. It also seems to be able to multiply Meliodas himself, so far being shown to be able to produce up to four copies, resulting in five Meliodas.

Trivia

 * Lostvayne is the fourth Sacred Treasure to be revealed in the series.
 * Lostvayne was worth 50 gold pieces when Meliodas sold it in a market in Camelot.