Path of the Grim Reaper

Barbarians who walk the Path of the Grim Reaper uses their Rage to draw in Souls inside of them to fortify their mortal shells.

Level 3: Soul Harvest

Whenever you hit a creature recklessly for the first time, you gain Temporary Hit Points equal to half of the damage you dealt (Maximum of 10 HP per Creature). Cannot gain temporary Hit Points on creatures that are Undead or Constructs.

Level 6: The Haunting

Whenever you activate Rage, all hostile creatures within 60 feet make a Wisdom Saving Throw. Failure: They become terrified of you and become unable to make actions until they succeed the repeat Saving Throw at the end of their turns. Each Failure adds a +5 bonus to their next Wisdom Saving Throw to end this effect.

Level 10: Reaper's Guillotine

Once per turn, whenever one of your attacks hit, add bonus Shadow Damage equal to any number of Temporary Hit Points gained through Soul Harvest. These Temporary Hit Points are consumed by this effect.

Whenever you active The Haunting, you now also gain Temporary HP equal to your Barbarian Level. This counts as Temp HP gained through Soul Harvest.

Level 14: Grim Avatar

Whenever you activate The Haunting, a nightmare-ish simulacrum of yourself, completely obedient to you, manifests from your body. Its turn is taken directly after yours. This Avatar has Hit Points equal to 10 plus 5 times your Level and has a Fly Speed equal to your Movement Speed. Its Creature-Type is Undead and its Armor Class is equal to 10 plus your Constitution modifier and your Charisma modifier. The Avatar can make one Attack and its Attack Roll and Damage is equal to one of your Attacks. Any Damage made by your Grim Avatar is Harvested as Temporary Hit Points. Souls may be repeatedly Harvested from the same Creature. The Avatar can also use its own Reaction to intercept and take damage that was intended for you.