This subclass uses a stance system that will use 2 - 3 options. 

Bonus Proficiency

Bonus Proficiency

When you choose this archetype at 3rd level, you gain proficiency in one of the following skills of your choice: History, Insight, Performance, or Persuasion.

You also gain a Katana. ( Go over this with your DM)

The katana is a martial weapon that deals 1d10 slashing damage with the Two-handed and Finesse properties.

Kamae

You are disciplined in your training by following the basics. You gain the ability to use the following stances while in combat wielding a katana. At the beginning of combat or when you draw your Katana you choose what stance to start in. You may change stances as an Bonus Action.

Wind Stance - While in this stance, you gain +2 AC.

Stone Stance - While in this stance, before you make an attack with your katana, you can choose to take a -5 penalty to the attack roll. If that attack hits, you add +10 to the attack's damage.

Water Stance - While in this stance, when a creature misses you with a melee attack, you can use your reaction and make a melee weapon attack against the creature. 

Elegant Courtier

Starting at 7th level, your discipline and attention to detail allow you to excel in social situations. Whenever you make a Charisma (Persuasion) check, you gain a bonus to the check equal to your Wisdom modifier.

Your self-control also causes you to gain proficiency in Wisdom saving throws, and you can give yourself a bonus to your initiative rolls equal to your Wisdom modifier.

Master of the Blade

At 10th level, your stances gain additional bonuses. 

Wind Stance - While in the stance, When you hit an enemy with a melee attack you may move half your speed without provoking an attack of opportunity. You may use this only once a turn. Your attacks now deal an additional 1d10 Lightning damage while in this stance.

Stone Stance -While in the stance, you may use your bonus action to make an additional attack. Your attacks now deal an additional 1d10 Force damage while in this stance.

Water Stance - While in the stance, You may use your bonus action to reduce an enemy's movement to 0 until your next turn, as long as they are size large or smaller.  Your attacks now deal an additional 1d10 Cold damage while in this stance.

Spirit of the Samurai

at level 15 you can attack with your katana at a distance,  infusing the attack with your fighting spirit.

Make a melee attack with a katana you can add 35ft to your attack range. The damage type is associated with your stance. You can do this two times your proficiency bonus, and you regain the uses after a long rest.

Wind stance deals Lightning damage.

Stone stance deals Force damage.

Water stance deals Cold damage.

Strength Before Death

Starting at 18th level, your fighting spirit can delay the grasp of death. If you take damage that reduces you to 0 hit points, you can use your reaction to delay falling unconscious, and you can immediately take an extra turn. While you have 0 hit points during that extra turn, taking damage causes death saving throw failures as normal, and three death saving throw failures can still kill you. When the extra turn ends, you fall unconscious if you still have 0 hit points.

Once you use this feature, you can’t use it again until you finish a long rest.