Whatever made this weapon, its flesh appears to be alive. It could be an abomination's blood magic, a spirit twisted into physical form, or some other affront to the gods. The power thrills right up your arm...
Maker: The Pit
Unique Attributes: Harm
Weapon (greatsword), legendary (requires attunement by a non-good alignment).
When attuned to the Clasping Maw, the wielder gains a +1 bonus to attack and damage rolls made with it. When the wielder hits with an attack using this weapon, and that creature was injured with this weapon on their previous attack, they deal an additional 2d6 slashing damage.
The bonus to attack and damage rolls increases to a +2. The damage bonus to striking a creature the wielder has already injured increases to 4d6. When a creature is damaged by this weapon, they suffer disadvantage on Strength ability checks until the beginning of the wielder's next turn. When the wielder drops a creature to 0 hit points with an attack using the Clasping Maw, they can immediately make an additional melee attack with this weapon as a bonus action.
The bonus to attack and damage rolls increases to a +3. The damage bonus to striking a creature the wielder has already injured increases to 6d6. When the wielder scores a critical hit with this weapon, the target must make a DC 17 Wisdom saving throw or become frightened of the wielder for 1 minute. If this saving throw is successful, not only does the target not become frightened, they become immune to this frightening effect for the next 24 hours.
Second Era Edit
Found shortly after the planeswalker opened the planar rifts, the Clasping Maw became a source of endless trouble for the Empire of Bael Turath. Some said that the sword was pure evil, passed through a planar rift from the abyss. Whether or not that was true, it was used in the service of evil by demon-worshipers and cultists for ten thousand years. Each time the Knight Protectors of Nerath or the Steel Vanguard killed the Clasping Maw's wielder, it was at great cost, and the sword was always reclaimed by the forces of evil. The Clasping Maw was wielded by diabolists, necromancers, alienists, and even by bandits, criminals, and pirates. It owes loyalty to none, and harm to all.