Necrotic Moon Bolt
Starting when you choose this tradition at 3rd level, you can hurl chilling bolts of necrotic energy.
You gain a new attack option that you can use with the Attack action. This special attack is a ranged spell attack with a range of 30 feet. You are proficient with it, and you add your Dexterity modifier to its attack and damage rolls. Its damage is necrotic unless the target would be immune, in which case it is cold, and its damage die is a d4. This die changes as you gain monk levels, as shown in the Martial Arts column of the Monk table.
When you take the Attack action on your turn and use this special attack as part of it, you can spend 1 ki point to make the special attack twice as a bonus action.
When you gain the Extra Attack feature, this special attack can be used for any of the attacks you make as part of the Attack action.
Waning Embrace
At 6th level, you gain the ability to channel your ki into a cold protective force. Immediately after you are hit by an attack, you can spend 2 ki points to cast the Armor of Agathys spell as a reaction.
You can spend additional ki points to cast ]Armor of Agathys as a higher-level spell. Each additional ki point you spend increases the spell’s level by 1. The maximum number of ki points (2 plus any additional points) that you can spend on the spell equals half your monk level.
Dark Side Burst
At 11th level, you gain the ability to create an orb of shadows that erupts into a devastating explosion. As an action, you magically create an orb and hurl it at a point you choose within 150 feet, where it erupts into a sphere of necrotic shadow for a brief but deadly instant.
Each creature in that 20-foot-radius sphere must succeed on a Constitution saving throw or take 2d6 necrotic damage. A creature doesn’t need to make the save if the creature is behind total cover that is opaque.
You can increase the sphere’s damage by spending ki points. Each point you spend, to a maximum of 3, increases the damage by 2d6, alternating between cold and necrotic damage.
Tongue of the Sun and Moon
Starting at 13th level, you learn to touch the ki of other minds so that you understand all spoken languages. Moreover, any creature that can understand a language can understand what you say.
Full Moon Shield
At 17th level, you become wreathed in a luminous, magical aura. You shed bright light in a 15-foot radius and dim light for an additional 15 feet. You can extinguish or restore the light as a bonus action.
If a creature hits you with a melee attack while this light shines, you can use your reaction to deal necrotic damage to the creature. The necrotic damage equals 5 + your Wisdom modifier and reduce their speed to 0. This also triggers the Waning Embrace.(see level 6).