A goliath of the name Yorn was a monk, and throughout his training he believed there wasn't enough focus on martial arts themselves. So he sought to make his own style of combat. But it was very quickly denied by the head masters. So Yorn went on aa journey to the north, where he knew tribes of barbaric peoples roam. That is when he found his way to the Tyr, a peoples who fought each other relentlessly for sport. Yorn saw his opportunity and formed a school in the tribe. Where other ways of monastic tradition teach their pupils to become masters of using the magical force in all living things, the newly founded the Way of the Closed Fist teaches students to become unrelenting, unstoppable forces of strength. They learn to overpower the strongest foes and to withstand blows much stronger than themselves, to throw punches that throw foes off of their game. The students of this school stand up against the harsh world, fighting against a world that tries to keep them under others. What they learn is that when you don't have any further to fall, it's a hell of a lot easier to stand back up.

Breaking Tradition

When you take this tradition at 3rd level, you can use your Constitution modifier in place of your Dexterity modifier for you Unarmored Defense feature

Guard

As a fighter, you know how to take a beating and how best to absorb the damage of even the hardest hits. Starting at 3rd level, as a reaction to taking damage, you can spend 1 ki point to gain resistance to the damage dealt by one attack or damaging effect until the start of your next turn.

Jab

The jab may not be as flashy or as strong as other punches but it makes its name as being the greatest and most fundamental punch in a fighters arsenal. It's speed, penetration and ability to set up for any other punch gives it this famous quality. Starting at 3rd level, before you make unarmed strike you can designate it as a Jab. When you do so, you gain a +5 bonus to the attack roll for this attack. Should this attack hit, it will deal half damage. In addition, if your Jab hits, the next unarmed strike you make on your turn has a critical hit range of 15-20.

Counters

At 6th level, your experience in fights has to lead you to the realization that a stronger opponents power can be used to their detriment. You gain the following Counters:

• Cross: If an enemy within 5 feet of you targets and misses you with an attack, you can use your reaction to spend 1 ki point to make an unarmed strike against the enemy, with a +5 to the damage. 
• Absorb: When a creature makes an attack roll against you may use 2 ki points to attempt an absorb. On attempt you contest the attack roll with an athletics check. If you match or surpass their attack you ignore the attack and gain temporary hitpoints equal the amount of damage that would've been done. If successful you regain 1 ki point.
• Duck n' Dash: When a creature misses you with a ranged attack, you can spend 1 additional ki point to move up to half your speed towards the creature.

Power Strikes

You learn how to increase the force behind your punches, improving their destructive power. At 11th level, you may use any of the following power punches when you land a critical hit with an unarmed strike.

• Liver Knee: You force the creature to make a Constitution saving throw or be incapacitated until the end of your next turn.
• Front Kick: You force a Large or smaller creature back 5ft. They then must make a Strength saving throw or be pushed back an addition 15ft. If they hit a wall the creature and the wall take 1d6 damage per 5ft they moved before hitting the wall.
• Hook: You roll the damage die of your unarmed strike twice when determining damage for this attack.

Additionally, anytime you have advantage on an attack roll against a creature, you have a critical hit range of 15-20.

K.O Strike

Every fighter, be they experienced or new, seeks to land the punch that ends not just the fight, but all fights onward. The punch whose impact echoes into the future as a reminder of who the champion is, of who sits on the throne, of who is the strongest. Perhaps, you can land such a blow.

Starting at 17th level, you build up a K.O. Gauge against an individual opponent by landing blows against them. Connecting with an attack against an enemy increases your meter by 1, while hitting with a critical hit increases your meter by 2. When your gauge reaches 20, you can attempt a K.O. Punch. Make an unarmed strike as a Power Punch against that creature, on a hit the target must make a Constitution saving throw. On a failed save, provided the target has 100 or fewer hit points, the target drops to 0 hit points. On a successful save or if the target has more than 100 hit points, they take an additional 10d10 bludgeoning damage from the unarmed strike. If the attack misses the target, the target takes 5d10 bludgeoning damage and must succeed on a Wisdom saving throw against your Ki Save DC or become frightened of you for 1 minute as the force behind the attempted blow strikes fear into their heart. Your K.O. Gauge resets to 0 after a K.O is attempted, when you make an unarmed attack against a different creature, your chosen foe is killed, when the encounter is over, or when you fall unconscious. Clones or illusions of that single creature do not count as a different creature for the sake of this ability.