The Vengeful Soul

Beneath the disarray of broken stone columns, cobwebs, and decomposing body parts, the man finds the weapon of one who's been damned. He removes the weapon from the tomb and goes on his hunt. A hunt to find the ones who wronged him. A hunt for Vengeance.

The Blade of Vengeance

Starting at 3rd level, as a bonus action, you may summon the Blade of Vengeance into your empty hand. You are proficient with it while you wield it, and it counts as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage. The Blade of Vengeance disappears if it is more than 5 feet away from you for 1 minute or more. It also disappears if you dismiss the weapon (no action required) or if you die.

Keeper of Souls

Also starting at 3rd level, once you reduce a creature to 0 Hit Points with the Blade of Vengeance, their souls will be forever trapped inside the Blade; imbuing you with strength and vengeance, gain temporary hit points equal to your fighter level + your dexterity modifier (minimum of 1).

Gaze of the Damned

Starting at 7th level, the energy of the Blade of Vengeance begins to course through your veins and the trapped souls within begin to resonate in you. Once per long rest, you may use the energy to gaze at a creature within 30ft of you and that creature must succeed on a constitution saving throw, with a DC of 10 + your dexterity modifier + your constitution modifier, or be frightened of you and take 2d10 psychic damage on a failed save and half as much on a successful save.

Wails of the Imprisoned

Starting at 10th level, you feel a sense of darkness overcome you, as those in your presence feel a sense of uneasiness. You gain expertise in the Intimidation skill and the Deception skill as the souls of the ones you trapped begin to wail from the scabbard of the Blade of Vengeance.

Thirst for Vengeance

Starting at 15th level, your need for vengeance engulfs your mind and the rage within controls you. On your turn, if you take the attack action and you hit a creature, then you may treat that damage as a critical hit and double the amount of damage done to the creature. You may do this once per turn.

True Vengeance

Starting at 18th level, you gain the power to temporarily release the souls you have conquered to do your bidding fo you. You may cast the Circle of Death spell twice per long rest. The Spell Save DC is equal to your fighter level. Also, on a failed save, the effect leaves the creature paralyzed for 1 minute. Or, on a successful save, the effect leaves the creature frightened for 1 minute.