This Greatsword has hook-like barbs along the edge to the blade that extend and retract in a scooping motion as an attack is made with it. When a creature makes an attack with this weapon and fails the attack roll by 3 or less, there is a 25% chance that either the target's Armor Class is reduced by 1. When the attack roll is successful, the target can choose to either take an extra 2d6 slashing damage or reduce their Armor Class by 1. The armor class of a creature can only be reduced to their passive Armor Class (10 + Dexterity Modifier). 

It an attack roll with the Anti-Armor Greatsword is a critical hit the target sustains a major injury, and must roll 1d6 on the injury table to determine what kind of injury they sustain

Attack rolls against objects with this weapon deal the maximum possible damage

Injury Table

1 The target's arm or leg is cut off at either the shoulder or hip

2 The target's arm or leg is cut off at either the elbow or knee

3 The target's hand or foot is cut off

4 The target sustains damage to a nerve and has disadvantage on Strength and Dexterity Checks and Saving Throws, and disadvantage on attack rolls 

5 The target sustains organ damage and takes 1d6 damage every round

6 The target sustains a mortal wound and takes 1d4 damage every round as they bleed

Each of these effects can be ended with magic such as Lesser Restoration or Greater Restoration (depending on the severity). Cure Wounds can heal hit points, but will not be able to end this effect. The effect of losing a limb will be up to the DM's discression.

Proficiency with a Greatsword allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Heavy, Two-Handed, Graze