Bloody Strike

You aim you next attack carefully and slice major veins and arteries. Your next successful melee attack deals extra damage equal to your spellcasting modifier. The target of the attack takes 1d4 damage each turn. The target of the attack or an ally within 5ft must use an action make a medicine skill check with a DC equal to your spell save DC, or use an action to expend a use of a healers kit to stop this effect.

 At Higher Levels: Add an additional 1d4 damage per turn at 6th level, 12th level, 16th level and 20th level.