Path of the Hallow Soul

Most barbarians are known for their overwhelming strength. When on the battlefield, barbarians are beings of endless fury, terrifying their enemies with a rage-filled roars. But those who are hallow, are different. They don't release their anger in a wrath-filled rage, they become blank, a shell of their former self. Their only intent being to destroy whatever is in their path, but not while yelling and screaming, while completely void of all emotion.

Blank slate

At 3rd level, those of the Hallow Soul enter a state where the rest of their emotions turn off, and the only thing left is the intent to destroy. 

While raging, any enemy who attacks you, you gain advantage on all attack rolls against that creature until the end of your next turn, or if you are hit by another enemy.

Additionally, against the selected creature, you can add 1d6 force damage to your first attack per round. This bonus increases as you level up. 1d8 at level 5, 1d10 at level 10, and 1d12 at level 15.

Deadly Intent

Starting at 6th level, your mind no longer focuses on anything else but your target, and it can't be penetrated by others intentions. You can no longer be charmed or frightened while raging.

Additionally, your intent to destroy makes you aware of all enemies, you can also no longer be surprised.

Undying Resolve

At 10th level, your body has evolved to overcome the wall that is emotion and go past it's limits. When entering a rage, you gain temporary hitpoints equal to your barbarian level x 2. If you have any excess hitpoints once your rage ends, they will be discarded. 

Once you use this feature, you can't use it again until you complete a short rest. 

Peaceful Nothingness

At 14th level, barbarians of the Hallow Soul reach a point where their mind is fully clear, nothing at all besides the intention to destroy their foe is left. Even though the intent is murderous, a clear mind is truly peaceful. While raging, you gain resistance to all forms of damage from all other creatures besides your quarry. But, because your mind is so clear, once you enter a rage and you gain a target, you can no longer switch targets unless they die, or your rage ends.