A creature that gets the drop on you is met with a swift and brutal reply. When you take damage from a creature within your reach, you can use your Reaction to make a melee attack with a weapon or an Unarmed Strike against that creature. You can use this feature a number of times equal to your Proficiency Bonus, regaining all expended uses when you finish a Long Rest.
Focused Ruthlessness. If you take this trait twice, you have Advantage on attack rolls made using Ruthless Response.