Chain Massacre (Patreon)

Greatsword, artifact (requires attunement by a Creature of Evil Alignment)

The masterwork of a twisted demonic artificer, this greatsword has an engine powered by hellfire and a chain system with sharp iron spikes that rotate around the blade at high speed.  You gain a +3 bonus to attack and damage rolls made with this magic weapon.

Odd weapon. Whenever you hit a creature with this weapon and roll an odd number on both damage dice, you can immediately roll another damage dice. You can keep rolling extra damage dice until you roll an even number. For every extra damage dice you roll, the weapon gains an Overheat Charge.

Overload. You can use your action, push the blade's engine and rotate it to strike all creatures around you. Make a melee attack with this weapon against every creature at 5 feet from you. For every creature you hit after the first, the weapon gains an Overheat Charge.

Interlock. If you hit an enemy using medium or heavy armor, make a DC17 strength saving throw. If you fail the chain massacre, get stuck in the creature’s armor. You and the creature are grappled, and either of you can use your action to make a DC17 strength saving throw to free itself. As long as this magic greatsword remains trapped, you can use your action to cause 2d6 slashing damage to the target. For every time you cause damage this way, the weapon gains an Overheat Charge.

This magic weapon can uphold ten Overheat Charges. As long as it is fully charged, it loses all its magic properties. The weapon loses one Overheat Charge every turn it remains unused.