Blood for Blood

You feel the bloodlust boiling inside you, and you embrace it with abandon. You revel in the sensation of power that courses through your veins, even as you bleed from self-inflicted wounds. While raging, as a bonus action, you can choose to strike with a savage ferocity, trading your own blood for deadly power. 

Prerequisites:

• At least four levels in Barbarian

Modifier:

• +1 bonus to Constitution

Mechanics:

1. Roll up to three d4s and subtract the total rolled from your current hit points.
2. Add the total rolled, plus your Constitution modifier, to the damage roll of your next melee weapon attack. The attack is made at advantage.

Limits:

• You have three dice to spend on this feature, which you can use any number of dice per attack until the three dice are expended. The dice count resets on a long rest.
• The additional damage dealt increases in potency as you gain levels. At 8th level, the dice size of the additional damage increases to d6, at 12th level to d8, at 16th level to d10, and at 20th level to d12.