When you finish a Long Rest, you can brew a number of Stim Potions, invigorating concoctions of herbs, equal to your Constitution modifier. These potions retain potency until you finish a Long Rest, after which they become inert.
When you drink a Stim Potion as a Bonus Action and at the start of each of your subsequent turns for 1 minute, you can choose one of the following benefits (no action required). When you use one of these benefits, you take Necrotic damage equal to one roll of your Battle Die. This damage ignores Resistance and Immunity and bypasses Temporary Hit Points.
Bullet Time
The next attack made against you before the start of your next turn has Disadvantage.
Hyper Focus
You have Advantage on the next attack roll you make before the end of your turn.