Way of the Magic Blockers

Magic users are feared foes by almost all beings. Their abilities warp reality to turn swords and shields to dust, and master strategists find their minds muddied by distant spell weavers. Your studies have led you to understand magic in a new way. It is power like any other, difficult to withstand when it is brought to bear, but meaningless when it is unable to move.

By carefully combining your knowledge of physical bodies and ki, you have learned how to disrupt casters and to take away their ability to wield their greatest weapon. Your talents are attractive to many individuals, from those seeking to unseat powerful evil wizards, to dark lords of the underworld who seek to undermine their greatest foes.

Steal Voice

Beginning at 3rd level when choosing this tradition, you can strike your opponent in such a way as to keep them from speaking for an extended period of time. When attacking any opponent, you can expend a Ki point to steal their voice. If the attack deals damage, the opponent must succeed on a Constitution save (DC 14 + damage from the attack) or be unable to speak for one round. This prevents the target from casting any spells with a verbal component.

Wave of Resistance

Beginning at 6th level, you are able to project a protective wave of ki that suffuses beings with a natural resistance to magic. Spend 1 ki point to take a standard action and emit a Wave of Resistance. Everyone within a 5-foot radius of you (including yourself) gains advantage on Spell Save checks for 1d4 turns. 

Cut Connection

Starting at 11th level, you use your connection with a target's ki to sap some of their energy for casting spells. Before making an attack, spend 1-3 ki points. If the attack is successful the target expends one spell slot, with level equal to the number of ki points spent.

The target regains all spell slots expended in this way after a short rest.

Antimagic Reflexes

Upon reaching 17th level, you have become a master at reading the body language of spell casters. Whenever a character attempts to cast a spell within 5 feet of you, you can expend 1 ki to make an attack as a reaction. If this attack hits, the spell caster fails to cast the spell and additionally loses the spell slot that was originally intended to be used.