Great Weapon Defence

You've mastered a defense style of fighting that nonetheless packs a powerful punch, in that you are capable of wielding two-handed weapons as defensive shields or otherwise intercept attack with the bulk of the weapon itself. You skillfully spin your body and weapon to counter foes who move against you. You gain the following abilities:

• On your turn, as a bonus action, you may enter a defensive stance if you are wielding any two-handed weapon. While you are in this stance you gain a +2 to your AC, and your movement speed is halved. This stance lasts until you attack something.
  
  
• By spending an additional 5ft per 5ft of movement you may move without provoking attacks of opportunity.
  
  
• If you are wielding a two-handed weapon and a target provokes an attack of opportunity from you, you may add your proficiency bonus to the damage of that attack.