At the start of combat, you hone your senses to strike quickly when the opportunity presents itself.

When you roll initiative, you can roll your Mastery Dice. You gain a number of Bonus Reactions equal to half the rolled amount (rounded down). These Bonus Reactions can only be used to perform an Attack of Opportunity. Once you use a Bonus Reaction, you cannot use it again during this combat. After you’ve used this ability, you cannot use it again until after you’ve taken a short or long rest.