Path of the Soulhugger

It doesn't end at death though, these barbarians think that once their opponent is defeated, they must rip their soul from their body. These Barbarians are willing to be corrupted by their enemies souls so that they can gain power.

Soul Scavenger

Starting when you choose this path at 3rd level, your health can benefit from slaying opponents. When you defeat an opponent you can use a bonus action to gain hit points equal to half of their hit point maximum + your strength modifier. If the hit points that you gain exceed your hit point maximum, then add them to your hit point maximum. You can use this ability an amount of times equal to your strength modifier. You can take a long rest to restore these uses, but your hit point maximum shall be reset.

Revenant Rage

Starting at 6th level, you can sacrifice yourself for your hunger for souls. While raging, you can expend your hit points to deal extra damage. When you attack  you can expend as many hit points as the attacks initial damage + your strength modifier. When you use this skill you also gain a bead of souls, which you can make a necklace out of.

Bloody Bead

Starting at 10th level, you gain the ability to use beads that you have attached to your necklace. You can use five of these beads to empower you with hunger for souls. If there is an enemy within 30 feet of you that has a lower hit point maximum than you, then you can expend one of your beads to try to rip their soul from their chest. You must first roll against your target's constitution score, if you succeed, the target must make a constitution saving throw against your roll. On a success, the target takes no damage. On a fail, you consume the target's soul, dropping it to 0 hit points.  You can use this ability equal to your strength modifier. You also must have five of these beads for each use. All uses reset after a long rest.

Vicious as a Vampire

Starting at 14th level when you gain this ability your dexterity score goes to 18 if it isn't already and you gain the ability to avoid death. You become immune to necrotic damage and to piercing damage. When you rage you take on a vampiric form, where you can not be damaged for your first two turns of combat.