Some reach enlightenment by languid meditation - others do so in the heat of battle. Monks manipulate ki to empower their own strikes and debilitate their foes.
Monks are unarmed combatants capable of spending Ki Points to perform special abilities. Monk's key ability scores are Wisdom, Dexterity, and Constitution, and their core ability is Unarmed Strike.
Monk weapons are melee weapons the Monk has Proficiency with, and which do not have the Two-Handed property. Versatile weapons count as Monk weapons even if they are wielded with both hands. Monks can use Dexterity for those weapons, even if they do not have the Finesse property. Some Monk abilities, such as Martial Arts: Bonus Unarmed Strike, are limited to Monk weapons.
Spellcasting ability
Wisdom for the effective use of items, scrolls, and equipment.
Most Monk features use the associated weapon ability (eg, the better of Strength of Dexterity). However, Way of the Four Elements Monks use their spellcasting ability for their unique class features other than Fangs of the Fire Snake.[note 1]
You can spend these points to fuel various Monk abilities. Ki abilities which incorporate an unarmed attack use the higher of Dexterity or Strength for attack rolls and save DCs. This includes all offensive abilities outside of the Way of the Four Elements subclass.
Reduce the damage from a ranged weapon attack by 1d10 + your Dexterity modifier + your monk level.
If the damage is reduced to 0, you can use a Ki Point to Deflect the Missile.
Use your Reaction to reduce the damage from a ranged weapon attack by 1d10 + your Dexterity Modifier + your monk level. If the damage is reduced to 0, you can use a Ki Point to return the missile back to the sender.
Your agility lets you dodge out of the way of certain spells. When a spell or effect would deal half damage on a successful Dexteritysaving throw, it deals no damage if you succeed, and only half damage if you fail.
↑The logic seems to be that Fangs of the Fire Snake is just a rider on a normal unarmed attack, while the other abilities are imitating spells and so use the spellcasting ability.