Monks of the Way of the Defender have mastered the skills of avoiding attack and defending others.  They can both avoid being hit and punish those who attack their ally's.  Constantly in motion, they dodge attacks with fluid motions.  

Patient Defense Technique

Whenever you use patient defense you may use one unarmed attack as the same bonus action. When you hit a creature with that unarmed attack, you can mark the creature until the end of your next turn. This effect ends early if you are incapacitated or you die, or if someone else marks the creature.

While it is within 5 feet of you, a creature marked by you has disadvantage on any attack roll that doesn't target you.

 

Improved Unarmored Defense

While you are wearing no armor and not wielding a shield, your AC equals 11 + your Dexterity modifier + your Wisdom modifier.

At level 6, while you are wearing no armor and not wielding a shield, your AC equals 12 + your Dexterity modifier + your Wisdom modifier.  At level 11, while you are wearing no armor and not wielding a shield, your AC equals 13 + your Dexterity modifier + your Wisdom modifier. At level 17, while you are wearing no armor and not wielding a shield, your AC equals 14 + your Dexterity modifier + your Wisdom modifier.

Defensive Flurry

At 6th level, if you or a creature you can see within 5 feet of you is hit by an attack, you can roll 1 martial arts die as a reaction. Roll the die, and add the number rolled to the target's AC against that attack. If the attack still misses, you can make one unarmed attack against the attacker.

You can use this feature a number of times equal to your Wisdom modifier (minimum of once), and you regain all expended uses of it when you finish a long rest.

Flurry of Defense

Beginning at 11th level, whenever you use patient defense you may use two unarmed attacks as the same bonus action. When you hit a creature with that unarmed attack, you can mark the creature until the end of your next turn, marking up to two creatures. This effect ends early if you are incapacitated or you die, or if someone else marks the creature.  In addition, the first creature marked by you this round has its speed reduced to 0. 

While it is within 5 feet of you, a creature marked by you has disadvantage on any attack roll that doesn't target you.

Unerring Defense

At 17th level, your mastery of defense grants you extraordinary reactions. If you are hit with an attack roll , you can force the creature to reroll it. You can use this feature only once on each of your turns.