Demon-Destroyer Sword

The Demon-Destroyer Sword (Metsuma no Tsurugi) is an ancient Anti Magic Weapon in Black Clover, found in the central room of the floating dungeon in the Gravito Rock Zone. It is stored as writing inside an open grimoire and is summoned at will without any magic power. Unlike the Demon-Slayer and Demon-Dweller Swords, its blade ends in a wide edge with what looks like a clover symbol at the top; it was covered in dirt until Licht picked it up and the dirt fell away to show a shining blade, and it went back to its dirt-crusted look once it was taken into Asta's grimoire.

Besides cutting through magic with its edges, it has a special ability, Causality Break (VIZ: Fate Release), which absorbs and removes the effects of spells by cutting the link between cause and effect. Tendrils of Anti Magic reach out to whoever magic has touched and pull back into the sword, turning the blade black. Because it acts on causality, it undoes not only the magic but its effects, such as tissue damage from a magical poison, which the other three Anti Magic Weapons cannot do, and it is strong enough to undo Reincarnation Magic.

In Asta and Liebe's Unite form a circle forms in its crossguard and this power grows stronger, and after learning Zetten and mastering ki Asta can hold it to raise a barrier that cancels all incoming magic around him.