Path of Blood

An Eye for an Eye. A Tooth for a Tooth. These are the principals that fuel your fight. For every wound you take, you give it right back. Nothing will stop your hunger for combat, for vengeance, for blood. Besides, you know what they say, what doesn't kill you, makes your enemies wish it had.

Power From Pain

Starting at 3rd level, upon reaching certain damage thresholds, your rage grants you a further bonus to your damage rolls. While below half of your maximum hitpoints, your gain a +5 to damage made with Strength attack rolls. This is further increased to +10 while below one-quarter of your maximum hitpoints. The damage type is necrotic for the purpose of overcoming damage resistance.

You also gain resistance to necrotic damage while raging.

Blood Funnel

At 6th level, when a hostile creature is slain within 5ft of you, you can use your reaction to regain hitpoints equal to 2d4 + your constitution modifier. The die increases to 2d6 at 10th level and 2d8 at 14th level. 

You can do this a number of times equal to your proficiency bonus and regain all uses of this ability on a long rest.

Focused Fury

At 11th level, you gain advantage on attack rolls made against the last creature to deal damage to you.

Blood for Blood

At 14th level, while at 1hp, your damage bonus from 'Power from Pain' triples for one Attack. After that you fall to 0 hitpoints, your rage ends, but you are stable. If the target of the attack is slain by this attack, you instead remain at 1hp and your rage continues. You may use this feature no more than once per round and have a limited number of uses equal to your proficiency bonus. You regain all uses on a Long Rest.