Monks of the Way of the Iron Fist are the counterpart to those who train in the Way of the Open Hand and rival them as the ultimate Masters of Martial Arts combat⁠ but with a greater emphasis on unarmed attacks. They focus on Techniques that strengthen their resistances and crush their opponents, manipulate their own ki to achieve devastating results.

Iron Fist Technique

Starting when you choose this tradition at 3rd level, you can harness your ki to provide a variety of effects. Whenever you hit a creature with one of the attacks granted by your Flurry of Blows, you can impose one of the following effects on that target:

• It must succeed on a Constitution saving throw or take a −2 penalty to AC and Dexterity saving throws until the start of your next turn.
• It must make a Strength saving throw. If it fails, you can push it up to 15 feet away from you.
• It can’t take reactions until the end of your next turn.

Body of Steel

At 6th level, you gain the ability to bolster your defence and offence further using your ki. 

Iron Vest. As an bonus action, you can spend 2 Ki and gain resistance to bludgeoning, piercing, and slashing damage. Your iron vest lasts for 1 minute. It ends early if you are knocked unconscious. You can also end your iron vest on your turn as a bonus action. You must finish a short or long rest before you can use this feature again.

Heavy Hands. You've learned to completely relax during your attack, letting the weight of your hands and body empower your strikes. You gain the following benefits:

• Before you make an unarmed attack, you can choose to spend 1 Ki and take a -5 penalty to the attack roll. If the attack hits, you add +10 to the attack's damage. You can use this feature only once on each of your turns.
• You can sacrifice one of your attacks when you take the Attack action to roll 2 additional martial arts die when you make an unarmed attack.

Unwavering

Starting at 11th level, you can use your reaction to adapt a more rooted stance, shrugging off the impact when you are hit by a melee attack. When you do so, the damage you take from the attack is reduced by 1d10 + your Constitution modifier + your monk level.

If you reduce the damage to 0, you can make an athletics check to grapple the opponent in place if you have at least one hand free. If you grapple the opponent in this way, you can spend 1 ki point to try to pin a creature Grappled by you, as part of the same reaction. To do so, make another athletics check. If you succeed, the creature is Restrained until the grapple ends. You make these athletics checks with proficiency, regardless of if you have proficiency or not.

Erupting Fist

At 17th level, you gain the ability to strike with inhumane force. When you hit a creature with an unarmed strike, you can spend 3 ki points to empower your fist. When you do so, the target takes an additional 10 martial arts die damage. When you use this action, the creature and every creature within a 15 ft cone behind it must make a Constitution saving throw. If the creatures fail, they are knocked prone and take 10d10 force damage. If they succeed, they take half the damage and are not knocked prone.

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