At 3rd level you have chosen to devote yourself to a specific one handed weapon. Choose one weapon type as your mastery weapon that does not include the two-handed, special, or heavy property. As long as you wield it in one hand and nothing in your off-hand you gain the following benefits.

Your movement speed increases by 10ft

Increase the damage die by one step for your Mastery Weapon (1d8 to 1d10 etc.)

When you take the dodge action, you may use your bonus action to attack with your mastery weapon.

You may use either your Strength or Dexterity modifier on attack rolls and damage rolls with your mastery weapon.

Flourish At 3rd level, you gain proficiency in Performance checks, if you’re already proficient in it, you gain expertise, which means your proficiency bonus is doubled for any ability check you make with it. You may add your Strength or Dexterity modifier instead of your charisma modifier if you use your mastery weapon in the display.

Pursuer Starting at 7th level you have learned to wait for openings during combat. As a reaction, if you are attacked by a creature you can see outside of your range you may move your movement speed towards the target, if you would end moving within range of the target you may take an attack action. Or, if a creature would provoke an opportunity attack from you, you may instead make two attacks. You may use this feature a number of times equal to your Dexterity Modifier (minimum of 1) you regain all your uses of this ability after a short or long rest.

Momentum At 10th level you have mastered the flow of battle, turning the tides in your favor after every successive strike. Upon each of your turns if you hit twice with your mastery weapon, you gain +2 AC, 15ft of extra movement and advantage on Dexterity Saving Throws lasting until the end of your next turn. If you cannot move you also lose these bonuses.

Untouchable At 15th level you find it easy to deflect attacks and make quick escapes Opportunity attacks made against you are made at disadvantage, if your movement speed would be reduced to 0 it is instead reduced to half. In addition, your attacks of opportunity no longer use your reaction.