Beginning when you choose this archetype at 3rd level, your weapon attacks score a critical hit on a roll of 19 or 20. Once on each turn when you score a critical hit, you can make an additional attack with the same weapon, against the same or a different foe. If this happens on your turn and you have remaining movement, you can move normally between these attacks.
At 3rd level you gain the ability to focus your strength when it really matters. This allows you to add 1d8 to a weapon attack roll that missed, to the damage of an attack that hit, or to a Strength check or saving throw that failed. You can do this a number of times equal to your proficiency bonus, and you regain all uses on a long or short rest. At level 10, this increases to 2d6. At level 18, it increases to 3d6.