Blade of Endless Pain (5e Equipment)

Weapon (any weapon that deals slashing damage), legendary (requires attunement)

This weapon starts with no charges up to a maximum of 4 charges. A charge can be gained by taking 25 damage on a single hit made against you, by any creature. that creature must not be someone you deem an ally, and the damage must not be self-inflicted.

Burden of Pain. You have felt the burden of pain for too long, and you will release the pain you have suffered; all the stings, burns, and slashes. In response to being hit by an attack while you are holding this magic weapon, you can use your reaction and expend 2 charges to force the attacker to make a DC 20 Wisdom saving throw. On a failed save, the attacker takes psychic damage equal to the damage dealt to you plus 4d10. On a successful save, the attacker takes psychic damage equal to half of the damage dealt to you plus 2d10.