Boxer

 

Born in the ring

beginning at 3rd level you can use your bonus action to enter a boxing stance

Out-boxer: When you enter this stance, you gain a bonus +10ft to your base movement speed. While in this stance, you do not provoke attacks of opportunity by moving out of an enemies threat range.

Slugger: The slugger embodies everything brutal about the sport while in this stance you get a -2 to your AC but deal 1 extra d6 bludgeoning damage to every hit
(The extra damage and minus to AC goes up at 7th level to AC -3 and +1d8 damage 11th level -4 AC and +1d10 damage 15th level -4 AC and +1d12 damage)

Full guard: You steel yourself getting ready for a beating when you enter this stance your speed becomes 0 and you get a +2 to AC and 2 reduced damage from all physical sources  
while in this stance you focus on defense and therefore cannot take attacks of opportunity 
( AC goes up +3 to at 7th level +4 at 11th level and +5 at 15th level)

You can change stance as a bonus action but you must spend 1 ki point to do so

Fighters vitality

 At 6th level you know how to take a hit and stay in the fight

 Once per short rest you can use your bonus action to gain 1d10 hit points + your monk level

One hit wonder

At 11th level you know how to hit someone where it hurts

Once per long rest when you hit an enemy you can spend 3 ki points to deal an additional 2d12 bludgeoning damage and force them to make a constitution saving throw using your ki save DC
(ki save DC = 8 + your proficiency bonus + your Wisdom modifier

If the enemy fails the saving throw they are stunned additionally if they fail it by 10 or more they are knocked unconscious but are stable 

Show stopper

17th level

Once per long rest as you attack you can use this ability by targeting the weak points of a humanoid creature. Spend 6/8 ki points and choose between the following 2 options. 

1. You spend 6 ki points. You choose a single humanoid creatures limbs within melee range to attack in an attempt to cripple them. make a standard unarmed strike however. replace the base damage with 5d10 bludgeoning damage instead 

2. You spend 8 ki points. You choose a single humanoid creatures vital point within melee range. make a standard unarmed strike. however replace the base damage with 5d10 bludgeoning damage instead. If this attack hits the creature must make a constitution saving throw against your ki save DC. If the creature fails it dies and if it succeeds you deal an additional 2d10 bludgeoning damage

(Ki save DC = 8 + your proficiency bonus + your Wisdom modifier)

(you cannot use One hit wonder and this ability in the same Turn)

(this ability cannot be used in tandem with flurry of blows)