Path of the Blood reaver

Your blood flows with unnatural power, this results in abilities otherwise impossible by a normal mortal.

Sacrificial strike

Starting when you take this path at 3rd level, you may sacrifice health equal to or less than twice your total barbarian level per round to deal 1 additional  slashing, piercing, or bludgeoning damage for every two HP lost this way. This damage is considered magical for the effects of overcoming resistance. Additionally if you are raging you gain resistance to this act but deal damage as if you had sacrificed normally. You may not use this feature the round you rage.

Starting at level 6, When attacking with the sacrificial strike class feature you may deal half of the total damage to those in a 5ft half circle in front of you. When raging you heal for half of the aoe damage.

Harvester

You have unlocked the secrets of harvesting your pain, at 75% health you may add your proficiency bonus to damage for all weapons, at 50% health you gain resistance to magic, at less than 10 health your first attack that round is a critical strike. Additionally whenever someone is damaged by a source other than you in a 10ft radius, you may roll a d12 gaining that many temporary hit points. (Temporary HP does not stack)

Blood Aura

Once a short rest you may exude an aura 20ft in radius that causes your enemies to exhibit a similar blood lust to you, enemies are far more likely to target you with their attacks. While this aura is active you target someone in the radius and Mark them for death, they have disadvantage on a saving throw of your choice and you have advantage to attack them unless they pass a strength check (DC equal to 8+proficiency+constitution modifier)

Unholy recovery

Starting at 14th level, You may spend up to half of your unused barbarian hit die in battle to regain health as a bonus action. If this is done on the same turn as a sacrificial strike you regain twice the HP.