Overwatch

Fighter, 8th level, dexterity of 16 or more

You can unleash hell upon your enemies using your arrows, giving them no chance to get close to you.   When you choose this power, you can use your reaction to make an attack action using a ranged weapon whenever an enemy moves towards you. Attacks made with this feature have a -3 penalty to the hit roll but deal an extra three damage.   You can use this ability an amount of times equal to your dexterity modifier per long or short rest.