Bonus Proficiency

Starting at 3rd level, you gain proficiency with your choice of either jeweler's tools, smith's tools, or tinker's tools.

Metal Within, Metal Without

Also at 3rd level, the essence of metal reinforces your mind and body. Your hit point maximum increases by 3, and it increases by 1 every time you gain a monk level.

In addition, when you make a Wisdom, Intelligence, or Charisma saving throw, you can use your reaction to roll your Martial Arts die and add the result to the saving throw.

You can use this feature a number of times equal to your proficiency bonus. You regain all expended uses after finishing a short or long rest.

Inner Metallurgy

Lastly at 3rd level, you master the basics of your tradition's teachings: how to incorporate the spirit of metal into your attacks.

Once per turn, you can choose to use your ki to envelop your next unarmed strike with the essence of metal. That unarmed strike deals additional damage equal to your Martial Arts die on a hit and has added effects depending on your choice of metal.

Adamantine. If your target is a construct or object, you have advantage on the attack roll. On a hit, a construct or object takes additional damage equal to your Wisdom modifier (minimum of 1).

Cobalt. On a hit, attacks against your target using metal weapons and ammunition are made with advantage until the end of your next turn. This includes your unarmed strikes modified by the Inner Metallurgy feature.

Copper. You gain a bonus to the attack roll equal to one roll of your Martial Arts die.

Gold. On a hit, your target must make a Wisdom saving throw against your ki save DC. On a failed save, they are incapacitated by the gleam of your golden strike until the end of your next turn. Checks made to grapple or shove a creature incapacitated this way are made with advantage.

Iron. On a hit, your target must make a Strength saving throw. On a failed save, they are knocked prone. When knocked prone this way, a creature must use all of its speed to stand up and end the prone condition.

Lead. On a hit, your target must make a Constitution saving throw against your ki save DC. On a failed save, their motor skills are impaired until the end of your next turn, reducing their walking speed by 10 feet and causing their weapon attacks to be made with disadvantage.

Quicksilver. Your reach increases by 5 feet and you can choose to deal slashing or piercing damage instead of the normal bludgeoning damage. In addition, on a hit, your target must make a Constitution saving throw against your ki save DC. On a failed save, they take additional necrotic damage equal to one roll of their hit dice.

Silver. If your target is a shapechanger, you have advantage on the attack roll. On a hit, a shapechanger must make a Constitution saving throw against your ki save DC. On a failed save, they revert to their original form and lose any immunities and resistances they have to nonmagical attacks and damage until the end of your next turn.

Starfall Steel. If your target has the Innate Spellcasting or Spellcasting trait and this attack reduces it to 0 hit points, you regain 1 ki point.

Tungsten. On a hit, your target must make a Strength saving throw. On a failed save, they are pushed to an unoccupied space up to 15 feet away. If this movement causes your target to end within 5 feet of another creature or a surface, they collide and both take bludgeoning damage equal to one roll of your Martial Arts die.

You can use this feature a number of times equal to your proficiency bonus, and you regain all expended uses after finishing a long rest. While you have no uses available, you can spend 1 ki point to use this feature again.

Tempered Physique

At 6th level, your training allows you to embody the best qualities of worked metal.

You have resistance to acid and fire damage. You also have advantage on Constitution saving throws against exhaustion.