Big damage, big cost
Level 3
Reckless Draw.
Open Vein's STR damage multiplier is 2 higher.
Example: At level 3, your maximum cost is 4xSTR. At level 9, it is 6xSTR.
Level 7
Vital Strike.
Your melee weapon attacks against Branded enemies gain the Vicious property.
Level 11
That’s MY Blood.
(1/round) When an enemy deals damage to you, your next attack gains advantage.
Level 15
Killing Blow.
(1/Safe Rest) When you attack, you may pay LVL HP to auto-crit.