Path of Blood

Rage. A main feature of Barbarians, this sub class changes the way Barbarians rage works and what exactly it does. It now trigger when you get damaged, there is still a way of granting rage on your own at level 10, via the Frustration feature. This also grants a bonus when you do choose to exit rage so there is reason to do so.

Boiling Blood

Instead of entering rage as a bonus action you enter it when you get damaged. Rage now grants 1d6 damage (per class level starting from level 3) to enemies you attack, grants no resistances and lasts for 12 seconds (2 turns).  

Calmation

When you choose to exit rage as a bonus action, you gain +5 to your AC for 2 turns. 

Frustration

Beginning at 10th level, you can use your bonus action to deal damage to yourself out of pure frustration. When you do so, deal 1d4 (per class level) damage to yourself and add this to damage of your next attack divided by two. If you choose not to attack this turn, the bonus goes away. On subsequent turns, you can use your bonus action to increase this bonus further granting the previous effects of this feature + the amount of damage gained on the current turn, doing this will decrease your AC by 4 stopping at 0. The effect thats triggered on subsequent turns ends if you get hit or get knocked out doing so.

 

Retaliation

Starting at 14th level, when you take damage from a creature that is within 5 feet of you, you can use your reaction to make a melee weapon attack against that creature.