Many monks prefer to strike directly with the fist, or with weapon, using the force of the strike to deal damage. Some, however, imbue their bodies with elemental power through meditation and will, strengthening themselves for the front lines with devastating abilities and strong defenses.

Elemental Fists

At third level, you gain the ability to imbue your unarmed attacks with elemental power. Each time you hit with an unarmed attack, you may change the bludgeoning damage from the attack to Acid, Cold, Fire, Lightning, or Poison damage. If you change the damage type in this way, the attack deals additional damage equal to half your proficiency bonus.

Primordial Self

Also at third level, your ki is infused with primordial energy. You learn to speak Primordial, your Hit Point maximum increases by two per Monk level, and you regain one Ki Point each time you are take Acid, Cold, Fire, Lightning, or Poison damage.

Endure Elements

At sixth level you gain resistance to Acid, Cold, Fire, Lightning, or Poison damage. You may expend two Ki Points to change the damage type as a bonus action, and you may choose the damage type at the end of a long rest. In addition, when you are hit with a weapon or spell attack you may expend a Ki  point and use your reaction to gain resistance to all of the damage from that attack.

Elemental Supremacy

Starting at 11th level your mastery of elemental energy manifests. As an action, you may create any one of the effects below. Each use consumes 3 Ki Points

• You gain a number of temporary Hit Points equal to five times your proficiency bonus. While you have these temporary hit points and are hit by a melee attack, the attacker takes damage equal to two of your martial arts die.
• You surround yourself in elemental energy dealing damage to all creatures of your choice within 10 feet of you. The damage is equal to three rolls of your martial arts die and bypasses damage resistance.
•  You fill your fists with primordial power. For the next ten minutes, when you deal damage using your Elemental Fists feature you deal an additional 2d4 damage.
• You touch one creature within five feet of you and force them to make a constitution save against your Martial Arts DC. On a failure, they gain vulnerability to one damage type for one minute.

When you take this action you may choose the damage type from Acid, Cold, Fire, Lightning, or Poison damage.

Elemental Mastery

At 17th level you've honed your mastery of primordial forces to it's peak. Whenever you deal damage to a creature using your Elemental Supremacy feature, you may expend one key point per any damaged creature of your choice to force them to save against your Stunning Strike feature, following all other rules. In addition, your Endure Elements feature no longer expends Ki Points when used.