You are destined with the sword, you either spent your life learning it or you reached enlightenment during a tough spot but whatever the case, you are now on the path to sword mastery

Feeling the sword

When you choose this subclass at level 3 you have attained enlightenment in the ways of the sword, but it is not perfect
feeling the sword - level 3
You can gain proficiency with all swords and they count as monk weapons
you can feel the sword like it is a part of your hand: you can use flurry of blow with your sword instead of unarmed attack as it feel like a natural way to attack with your body
Moreover you can cover your sword and body with ki for 1 minute by spending 2 ki
for this duration, you add your wis modifyer to your ac

Soul sword

At level 6, you and your sword and are connected by soul
you can spend 2 ki points to infuse soul energy
Your blows can now steal the life force of your enemy, every time you damage your enemy, you can heal for the 1/2 attack's damage
Additionally your stunning strikes now use wisdom save

One with the sword

Beginning at 11th level, you have reached the highest level of coexistence with your sword. you can now take deadly stances 
you can channel 3 ki points to enter a deadly stance for 1 minute or until dropped. you can switch between the stances as a object iteraction (you chance the way your sword is wielded)
Unyielding- you add your attack modifyer to your unarmored defence
dragon- infuse your sword with sword aura, your attacks have advantage and you can do a additional attack when you take the attack action. additonally your critical range increases by 1
tranquility- for every turn you spend without spending ki points, you regain 3 ki points

Sword saint

At level 17, You have reached the pinacle of sword arts hence your stances are stronger
unyiedling- when you use the hollow body, you gain resistance to force damage and your aura radiates out letting you and your allies in 10ft distance take less damage equal to wis mod
Dragon- you can use flurry of blows twice
Ttanquility- in this state features that cost 1 ki, doesnt cost ki