Way of the Iron Heart

Monks of the Way of the Iron Heart forsake all magic and dedicate themselves to halting all uses of it. Different monks have different philosophies on how they should carry out the mission of this order, some only targeting what they see as abuses of magical power, others indiscriminately targeting all magic-users no matter who they are or what they do with their power.  Monks who join this order often do so out of vengeance or disillusionment from a specific magical disaster or attack. Others join because they feel that magic is too prevalent in their world and that it is ripe for people to take advantage of.

This subclass was inspired by the actual play show Dimension 20: The Unsleeping City Season Two.

Mage Slaying Technique

At 3rd level, you’ve trained relentlessly in the art of punishing spellcasters. When a creature within 5 feet of you casts a spell, you can use your reaction to make an unarmed strike against that creature. You can spend 1 ki point to make a second unarmed strike when you use this reaction.

In addition, you have advantage on saving throws against spells cast by creatures within 5 feet of you.

Determined Pursuit

At 3rd level, you learn to follow people through the magical rifts created by teleportation. As a reaction when someone within 5 feet of you teleports using a spell or another magical ability or effect to a different location on the same plane, you can follow them through the rips in reality they create, appearing within 5 feet of their destination.

Credit: Colby - @crit_fails on Twitter

Disallowing Strike

Starting at 6th level, you can target certain pressure points on the bodies of spellcasters to prevent them from casting spells. When you hit another creature with a melee weapon attack, you can spend 1 ki point to attempt a disallowing strike. The target must succeed on a Constitution saving throw or be unable to use verbal and somatic components to cast spells for 1 minute. At the end of each of the creature’s turns, it can make another Constitution saving throw, ending the effect on itself on a success. If this ability is used with the reaction granted by the Mage Slaying ability and the target fails the saving throw, the spell they are attempting to cast fails and has no effect if it requires a verbal or somatic component. 

In addition, when you damage a creature that is concentrating on a spell, that creature has disadvantage on the saving throw it makes to maintain its concentration.

Spell Annihilation

Starting at 11th level, you have trained in the destruction of existing and currently forming spells. You can spend 3 ki points to cast Dispel Magic or Counterspell without providing material components. If you make an ability check to stop an effect or spell while casting these spells, use your Wisdom modifier. In addition, you can cast these spells at a higher level by spending 2 additional ki points for each additional level of spell.

In addition, you are immune to being charmed or frightened by any spell.

Presence of Unyielding Will

Upon reaching 17th level, you’ve reached a point where you can disable magic through pure force of will. You gain the ability to cast Antimagic Field with a radius of 15 feet. Once you use this feature, you can't use it again until you finish a long rest or unless you spend 8 ki points to activate it again.