Way of the Adamantine Fist

Monks who follow the way of the Adamantine Fist believe that eschewing metal is folly.  They see the metal they take and forge as an extension of themselves, as much of a weapon than any weapon they can pick up along the way to their own form of enlightenment.   As a devotee of the Adamantine Fist, you craft your armor, and pour Ki and yourself into it, forging a bond that distorts mundane properties into a mercurial weapon that protects the wearer as much as strikes their foe.  To an Adamatnine Monk, the armor is both sword and shield, and is neither encumbered by it, or sees it as something separate from them.

Ki Infused Armor

At third level, your dedication to the Adamantine Fist has bore fruit, allowing you to craft Ki Infused Armor.   Ki Infused Armor grants you a set of medium armor that grants an AC of 14+proficiency bonus.   The Ki Infused Armor allows the monk to use monk abilities while wearing it and replaces the monk's Unarmored Defense while using it.  

In addition, you gain proficiency in Blacksmith tools, Medium Armor, and the mending cantrip (Wisdom is used for casting).

If the armor is destroyed or lost, the monk may create a new set involving 100 gp worth of materials, and 8 hours of meditating to become attuned with the new set of armor.

Adamantine Form

At level 6, you are able to enter into the Adamantine Form.  The Adamantine Form causes your armor to become as much of a weapon as your fists, allowing you to gain almost supernatural ability to warp and twist other materials as you strike it.  During your turn, as a free action, you are able to enter into the Adamantine Form, consuming 1 ki to do so.  While in the Adamantine Form, you are considered to have the following effects.

-You are concentrating on the Adamantine Form, as if you were concentrating on a spell.  You have advantage on all concentration checks to continue the form.
-The form lasts for 1 minute, until concentration ends, you are knocked unconscious, are killed, or end it as a free action.
-On your turn, once per turn, you are able to enter into either Breaker or Mercurial stance as a free action.

When you enter Adamantine form, you may choose to enter as Breaker or Mercurial, and gain the following effects.

Breaker Stance  
While in Breaker Stance, successful melee attacks against creatures wearing armor reduce their AC by 1.  You are able to reduce the AC of a creature a number of times equal to your Proficiency Bonus, after which further attacks against the same creature do not reduce the AC any further.   Creatures with natural armor instead may roll a Constitution save (DC equal to 8+Wisdom Modifier+Proficiency Bonus).  On a failed save, the target loses the AC as normal.  The AC loss lasts until the armor is repaired, while natural armor is regained after a long rest.  Breaker Stance has no effect on Magical Armor, Armor granted through magic (Such as Bark Skin or Mage Armor), or on AC granted through Dexterity bonuses.

Mercurial Stance
While in this stance, the melee attack range of your attacks becomes 10 feet, and become almost liquid.   Creatures you successfully hit with melee attacks must make a Strength saving throw (DC equal to 8+Wisdom Modifier+Proficiency Bonus) if they are large or smaller, or be restrained by until the end of your next turn.  You may only have one creature restrained at a time.  In addition, you have advantage on Athletics checks to escape grapples, Dexterity saves to avoid falling, and saves at being knocked prone or grappled.

In addition, even when not using Adamantine Form, you may spend Ki Points to do one of the following.
-As a reaction, you may spend a ki point to gain resistance to Bludgeoning, Slashing, and Piercing damage until the start of your next turn.
-Spend a ki point to gain climb speed equal to your movement speed for the next ten minutes
-Spend a ki point to gain a monk weapon that you can use of your choosing for the next hour.

Adamantine Body and Soul

Starting at level 11, your body and soul have merged with the metal.   While wearing your Ki Infused Armor, you gain the effect as if you are wearing Adamantine Armor, turning critical hits against you into normal hits, and is considered magical armor.   In addition, while wearing your Ki Infused Armor, you have advantage on Constitution saving throws.

The Iron Man

At 17th level, your armor becomes one with you.   You gain the following effects.
-You can wear your armor while sleeping and suffer no ill effects from doing so.
-Your Ki Infused Armor cannot be removed from you unless you are willing.


In addition, your Breaker and Mercurial Stances gain added effects.

Breaker
Your melee attacks gain an additional 1d6 extra bludgeoning damage per attack.   Once per round, enemies struck by you must make a Strength Saving Throw (DC equals 8+Wisdom modifier+Proficiency Bonus) or be knocked prone.  In addition, attacks made against objects that hit are considered critical hit while using unarmed strikes or monk weapons.

Mercurial
While in Mercurial stance, creatures that fail their saving throw against your stunning strike take an additional 1d6 bludgeoning damage.   Once per round, you may spend an additional ki point when using stunning strike to force an enemy to roll their saving throw with disadvantage.