Way of the Tiger's Vessel

The style is made up of four different katas, or forms, each of which must be fully mastered in order for the Niko Style to be complete. This style places a high focus on adaptability and applicability; many of the techniques are not set patterns, but rather basic principles which can be applied in multiple situations.

The Niko Style's Four Katas are Adamantine, Flame, Redirection, and Water. Each kata has an "Ultimate Technique" which are not necessarily the most powerful techniques but are rather "aces in the hole" that can be used no matter what condition the user is in.

Source: Kengan Ashura (Manga)

The Adamantine Kata: 
(Kongō no Kata; lit. "Adamant Form") involves the tightening of the muscles (thus hardening one's body) for both defensive and offensive purposes.
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The Flame Kata: 
(Katen no Kata; lit. "Heavenly Fire Form") is centered around movement and positioning, giving the user incredible speed and agility.
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The Redirection Kata: 
(Sōryū no Kata; lit. "Flow Control Form") involves seeing and manipulating the "flow of power", using minimal motions to turn the opponent's attacks against them. As a result, this kata requires incredible kinetic vision and delicate physical control.
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The Water Kata: 
(Suiten no Kata; lit. "Heavenly Water Form") is a grappling-based kata that places emphasis on flexibility and fluidity of motion.

The Nil Kata 
(Mu no Kata, lit. "Empty Form") it's not one of the four katas of the Niko Style per se, but rather a compilation of breathing exercises.

Niko Style Student. [3rd Level]

Upon choosing this subclass you gain access to the first tier of all four Katas. You gain access to the remaining tiers at 6th 11th and 17th levels

 Adamantine Kata
Indestructible (, Fue) - As a reaction, you can spend 1 Ki points to gain resistance to Bludgeoning, Piercing, Slashing, Cold, and Fire damage until the start of your next turn.

Allows the user to either defend from powerful blows or attack the opponent with immense power, by instantaneously clenching all of their muscles at the moment of impact; tensing and tightening of the muscles increases the solidity and density of the user's body, thus preventing the impact of outside attacks from inflicting much, if any, damage.
This gives the technique massive defensive and offensive power.


 Flame Kata
Flashfire (, Hibashiri) - As a bonus action you can spend 2 ki points to give all attacks against you disadvantage. In addition, you can move to an adjacent square of an enemy within 10 feet of you without invoking opportunity attacks, granting yourself advantage on all attacks until the start of your next turn.

This is a style of movement that allows for the user to flicker like a flame. This technique is able to confuse the enemy by creating afterimages. By controlling the pacing, placement, and timing of one's footsteps and movements, entering and exiting people's blindspots.

 Redirection Kata
Weeping Willow (, Yanagi) - When you are targeted for a melee attack, as a reaction you can spend 2 ki points, the target must succeed on a DEX save or be knocked prone, and their attack is negated (DC= 8+prof+WIS)

The most basic move of the Redirection Kata,  alters the trajectory of their opponent's attack by redirecting their flow of power. In this manner, the user can make their opponent's attacks miss as well as make an opponent lose their balance, allowing an opening for an attack.


 Water Kata
Bind of Pisces (, Sōgyo no Shibaru) - When you take the grapple action, you can spend 1 ki point. The target makes the check with a disadvantage.

 This is an armbar that involves immobilizing the opponent's arms by pinning one arm by their head with one's legs and the other arm with one's hands.

 

Adept Niko Style user. [6th Level]

Adamantine Kata
Ironbreaker (, Tessai) - When you take the attack action, you can spend 1 ki point per attack and add a 2d8 damage die to that attack.

This is a strike-enhancing technique that is delivered while tensing and tightening the muscles in the user's hands or feet. It produces attacks powerful enough to leave an impression of one's fist in their opponent's body.

Flame Kata
Phantom Pace (, Yūho) - When you are a target for an attack, as a reaction you can spend 2 ki points to force the attack to miss and move 5 feet away from the attacking creature without evoking an attack of opportunity.
[Note: This does not work against opponents that hit unerringly. Such as the "Storm Giant Quintessent" or "Marut"]

This is a technique where user quickly sidesteps at the moment right before their opponent's attack lands, causing the opponent to think that their attack phased right through them, leaving behind an afterimage.

Redirection Kata
Change of Scenery (, Tenchi)- When you are targeted with a melee attack, you can spend 1 ki point, The target must succeed on a contested acrobatics check or be pushed 10ft away in any direction before their attack begins. This only works on creatures one size larger than you or below.

This technique allows the practitioner to use the opponent's power against them, allowing them to hurl their opponent with a twisting throw.

Water Kata
Guillotine (, Shudan)- When you grapple a creature, you can spend 1 ki point as apart of the grapple to deal 2d8+Dex damage per round, as long as the creature remains grappled. If they're dropped to a critical state while grappled in this way (~10% hp) you may choose to break one of the opponent's limbs, potentially incapacitating them.
[Can be used in unison with Bind of Pisces.]

This is a technique that is performed while the opponent is off balance, the user grabs the front of their opponent's neck with both hands (while facing in the opposite direction to them) and then violently pulls and lifts their opponent's body up off the ground using their neck as a lever, heavily damaging the opponent's neck.

Nil Kata
Void - Once per Long rest you can spend 10 minutes meditating to gain ki points equal to your proficiency modifier, or 1 hour to regain ki points equal to twice your proficiency modifier. 

 

Expert Niko Style User. [11th Level]

Adamantine Kata 
Iron Fingers (, Tesshi)- As long as you have at least one free limb, you can remain on any horizontal or vertical surface in a state of suspension, gripping the walls and ceiling with your iron fingers/toes. Additionally, you can change the damage type of any unarmed attack from Bludgeoning to Piercing. (No Action Required). You permanently gain advantage on all grapple checks so long as your fingers are not broken. 

A technique that involves tightening the muscles in the fingers/toes thereby hardening the joints of the limbs. This is an extremely versatile technique and can be used as a jabbing attack against the opponent's vitals, as a pinching hold or even to enable movement of the fingers even if they are broken.

Flame Kata
Raging Fire (, Rekka)- When you take the dash action you can spend 1 ki point to add 10 ft to your movement speed until the end of your turn. In addition,  you can add 1d6 damage per 20 ft moved to 1 attack. You can spend multiple ki points to increase your movement speed up to your Dexterity modifier.

This is a sprinting technique that combines with Iron fingers. It is performed after digging one's toes into the ground, allowing them to accelerate at unthinkable speeds.

Redirection Kata
Entanglement (み, Karami)- When you take damage from a melee attack you can spend 3 ki points, the target must make a DEX save or their attack will be redirected back at them and they will be knocked prone and restrained. If successfully performed against a critical hit, you may choose to break their attacking limb. 

This is a technique that goes one step beyond the Weeping Willow. By not only altering the trajectory of the opponent's attacks but grabbing onto them while doing so, the user can redirect the power back into their opponent. This can cause dislocation of the joints.

Water Kata
Swimming Swallow (, Suien)- As an action, you can spend any amount of ki points to make that many amounts of unarmed attacks against that opponent with advantage unless the opponent has Blindsight or Tremorsense. In which case you'd lose the advantage.

This is a rush of blows with unpredictable and quickly-altering trajectories, making them incredibly difficult to guard against.

 

Niko Style Master. [17th Level]

Adamantine Kata
Bone Binding (, Hōkotsu)- As a Bonus action you can spend 2 ki points to gain temporary HP equal to 2d6+ your monk level. In addition, you can spend 1 or more ki points to add an additional d6 per ki point spent. This also temporarily fixes broken bones.

This is the ultimate technique of the Adamantine Kata. Using precise and delicate muscle control, the user is able to move body parts where a bone has been broken. 

Flame Kata
Earth-Shrinking (, Shukuchi)- As apart of your movement action, you may spend 3 ki points and force all creatures who see you to make a perception check contested by your acrobatics check. (Of which you make with advantage.) Upon meeting your check or below, they fail. You are considered hidden and may add a 9d6 sneak attack damage to any one attack you make. You may only use this feature once per long rest. 

The essence of this technique lies on "standing on one's bones alone" without the use of the muscles. It relies on shifting one's center of gravity to move, with its "interval" visibly different from regular motions. It yields the illusion that the user is backstepping and the distance between the user and the opponent suddenly shrinking.

Redirection Kata
Marionette (, Kugutsu)- Upon reaching half health, you may spend 4 ki points (No Action Required) and roll your martial damage die + your wisdom modifier. The resulting number would be the amount of techniques you may perform without expending ki points up to Expert level. You can only use this once per long rest.

The ultimate technique of Redirection Kata, Marionette amplifies the body's internal power and control their body with minimal usage of energy, enabling them to move and fight when their stamina is extremely limited.

Water Kata
Water Mirror (, Suikyō)- While you are grappled or otherwise restrained you can spend 3 ki points and instantly break out of that condition and optionally make a grapple attack against the same opponent as apart of the action with advantage, using their own limbs to restrain them. If you succeed this special grapple check, your opponent's considered to be both incapacitated and grappled.

The ultimate technique of the Water Kata can be used when the user cannot can't use their normal locks and holds, such as if they had broken their arm. This technique involves using a part of their opponent's body to place their opponent in a lock or a hold. Because there is no specific form for Water Mirror, it allows the user to be flexible and change the way they use it in a fight situation.

The Ultimate technique that the Niko style has, utilizing every single kata into a singular strike...

Secret Technique: Demonsbane (, Ōgi: Kiō)- When you would take damage from a melee attack you can spend 6 ki points to redirect the attack, hitting unerringly. The enemy takes your unarmed strike damage, the damage that would have been done to you, 5d8 additional damage and are knocked back a number of feet equal to half the damage dealt.
Only large and smaller creatures can be knocked back. This can only be used twice per short rest.

Demonsbane is the application of all four katas acting as one. As such, can only be performed by someone who has mastered all four. The training for the technique requires the user to have experienced the heightened sense of awareness that comes with a near-death experience. It is a counter that enables the user to completely ward the impact of an opponent's attack.
The user utilizes Redirection to change the direction of the attack's power, Water to allow the power to flow throughout the body and Flame to check positioning. Finally, Adamantine is used to deliver the diverted power back to the opponent while also adding their own power to the attack, drastically augmenting the damage inflicted.
Demonsbane is also a formless move, making it deceptively deadly because no matter what attack the opponent performs, the user can divert and return it back with more power.

Additionally, you can now use "Weeping Willow", "Flashfire", "Indestructible", and "Bind of Pisces" at no cost.