Path of the Bloodrush

Bloodrush barbarians use chemicals, drugs, and other stimulants to push them beyond normal physical limits. When they rage, they deal additional damage, and gain a random damage vulnerability. They also become more potent and lethal the more damage they take. 

First Rush

Starting when you choose this path at 3rd level, the damage your melee attacks is increased. While raging, your melee weapon attacks deal an additional 1d4 damage of your weapon's damage type times your proficiency bonus.

Bloodthirsty Rush

Beginning at 6th level, when raging, you gain a random damage vulnerability. In addition, for every 10 Hit Points you are missing, your melee attacks deal an additional 2d4 damage of your weapon's damage type. 

Frenzied Rush

Beginning at 10th level, you become bolstered by your stimulant-induced rage. If you take the Attack action on your turn, you may use your reaction to make two additional melee weapon attacks. If these attacks hit successfully, take 1d6 force damage for each attack that hit. If neither of the attacks hit, then you take no damage. 

Toll of Bloodrush

Starting at 14th level, if you start your turn with less than half your Hit Point Maximum, you can choose to multiply your weapon's damage dice by 2 for all melee weapon attacks that turn. At the end of that turn, gain a level of exhaustion. All levels of exhaustion are removed at the end of your next long rest.