Monks practicing this style look to cover up their weaknesses with techniques. Offering a Kata for each situation that they might find themselves in. Heirs of the Niko Style use their power to not abide by notions of ‘good’ or ‘bad’ just that those without power should be granted the chance to survive. Niko Style monks aim to balance their 4 Katas, while also struggling to tackle the new ‘spirit’ they’ve been given.

 

Credit to u/Prikkasaurus_Rex for the idea and inspiration.

Basic Katas

Starting at level 3 your ability to use the basics of the Niko style bare fruit as your ki lets you channel itself into 4 Katas.

• Adamantine Kata: Indestructible -By hardening your muscles you’re able to make your body suitable for both offense and defense.
  Whenever you’re hit by an attack you can spend 1 ki point as a reaction to gain AC equal to 1 roll of your martial arts dice, until the start of your turn.
  
  
• Flame Kata: Flashfire - Your rigorous training has gifted you with the ability to move at speeds some thought impossible.
  Whenever you use your step of the wind class feature you gain both the dash and disengage option.
  By spending an additional ki point you can cause the next attack against you to be at disadvantage.  
  
  
•  Redirection Kata: Weeping Willow - Whenever you look at someone while they fight their “flow of power” becomes apparent and you can use this knowledge to your advantage.
  Whenever you are hit by a melee attack you spend 1 ki point as a reaction to reduce the damage by 1d10 + your dexterity modifier + your monk level. If you reduce the damage to 0 in this way you can knock the enemy prone or push them 5ft away. An enemy cannot be pushed away or knocked prone if it is huge or larger.
  
  
• Water Kata: Bind of Pisces
  Rounding out your martial arts process is the ability to grapple an opponent with your flexibility and fluidity.
  You can now grapple with your dexterity modifier.
  If you take the grapple action on your turn and succeed, you can spend 1 ki point to cause the enemy to have disadvantage on the next attack roll or ability check it makes.
  

Possessing Spirit

Your understanding of the Niko Style has developed into an explosion of power. This technique was thought to be impossible, but was made to rival the rage of a barbarian.

Starting at level 6 you can spend 2 ki points as a bonus action to enter into an “advanced state” causing your heart to pump at inhuman levels. This heartbeat is audible to individuals within a 10ft radius. For the next minute you gain the following effects.

• You are resistant to BPS damage from non-magical attacks. 
• Your unarmed strikes deal an additional +2 damage.
• You make STR checks and saving throws with advantage. 
• Your movement speed increases by 10ft.
  

Your "Possessing Spirit" ends early if you are knocked unconscious.

You can use "Possessing Spirit" a number of times equal to half your PB (rounded up) per long rest.

Due to the harsh nature of this transformation you are unable to use any Niko Style technique or cast spells. After you end your Possessing Spirit your DM will note the side effects and the toll it is taking on your body.

If you have at least 17 levels in the monk class you can forgo the additional bonus damage and the advantage on STR checks and savings throws. If you choose to do this you can utilize your “Advanced” and “Basic” Niko Style Kata features.

Advanced Katas

Startling at level 11 your mastery of the 4 Niko Style Katas has developed even further. Allowing you access to advanced techniques once beyond your grasp.

• Adamantine Kata: Ironbreaker - You can now use your Adamantine Kata for offense instead of just defense. Tightening your muscles to give your punches and kicks tremendous impact.
  The next time you attempt to strike with an unarmed attack you can spend 1 ki point (before rolling) to double the martial arts die of your attack. If you land an attack this way you can use "Indestructible" as a reaction for no ki. If you have 17 levels of monk then the damage from Ironbreaker increases to triple your martial arts die.
  
  
• Flame Kata: Raging Fire - Your speed to the untrained eye appears to leave afterimages in your wake. The flame kata’s emphasis on movement and positioning have given you superior mobility.
  You can now dash as a free action a number of times equal to your wisdom modifier.
  
  
• Redirection Kata: Entanglement - Your understanding of the “flow of power” reaches new heights as even the most basic of movements become apartment to you.
  Whenever you use your “Weeping Willow” feature and reduce the damage to 0, you can spend an additional ki point to force that power back into their body. The target who attacked you takes damage equal to the damage they would have dealt to you.
  
  
• Water Kata: Seagrass Hold - Your ability to grapple has extended beyond the body and into the extension of it as well. Realizing that weapons are just as susceptible as people.
  After making a successful grapple attempt you can spend 1 ki point to disarm an opponent. You cannot use both “Seagrass Hold” and “Bind of Pisces” on the same grappled target.

Heir to the Niko Style

Starting at level 17 you are now a master of the Niko Style. Many might even refer to you as “Tokita Niko” despite having your own name. You can now utilize the ultimate techniques of the 4 Niko Style Katas, how to use the basics with little effort, and finally know how to combine your katas.

The "Basic Katas" can now be used without expending ki points, as your mastery of the basics has made using them as simple as breathing. In addition to this you gain the following new ultimate techniques of each kata:

• Adamantine Kata: Bone Binding - No matter if your bones are broken you are able to make a fist due to the precise understanding of your own muscles and body.
  You can spend a number of ki points equal to half your wisdom modifier (rounded up) as a bonus action to roll your martial arts die. For each ki point you spend you roll 1 of your martial arts die and gain that many hit points. 
  
  
• Flame Kata: Earth Shrinking - The ability to “stand on one’s bones alone” moving to you is no longer using your legs but more so shifting your shifting your center of gravity. To your opponent it might even look like you’re shrinking.
  You ignore any reduction to your speed based on exhaustion.
  If you took the dash action and moved at least 5ft on your turn the next unarmed strike you take is with advantage.
  
  
• Redirection Kata: Marionette - This ultimate technique makes you feel as if tiny strings are pulling your body, moving with the smallest amount of energy possible to conserve your stamina.
  While you are below one quarter of your HP you can use a number of niko style techniques for no ki equal to your wisdom modifier. Once you use have used niko style techinques in this way, you can't benefit from Marionette until after finishing a long rest.
  
  
• Water Kata: Water Mirror - Mastery of grappling is no small feat and you can now grapple even if part of your body is not full fucitionally (such as a broken arm).
  You are able to take the grapple action even if one of your hands is full and provided that your target has at least a leg or arm available.
  Upon making a successful grapple check you can use both your “Bind of Pisces” and “Seagrass Hold” on the same target for 1 ki point.
  

Ultimate Technique: Demon’s Bane
By mastering all 4 katas you have gained access to an incredibly powerful and risky technique, the “Demon’s Bane.” Through countless battles you now understand what it means to have a “near-death experience,” which is crucial for pulling off this technique. Redirection Kata to change the direction of the attack’s power, Water Kata to allow the power to flow throughout the body, Flame Kata to check positioning, and Adamantine Kata to deliver the power back to the appointment while also adding your own power.

When you would be hit by a melee attack, aren't currently under the effects of "Possessing Spirit," and take damage, you can spend 4 ki points to make a reaction attack against the attacking creature. If it hits, the enemy takes the full damage that it would have done to you plus an additional 5 rolls of your martial arts dice plus modifiers. If the attack misses you take the full damage from the original attack. If you wish, you can choose to activate Possessing Spirit for an additional 1 ki point on your attack granting you advantage on the attack roll and extra damage equal to half your monk level rounded up. After you make this attack roll “Possessing Spirit” will end.