(Based off of the Sun soul monk from Xanathar's Guide) Monks of the Way of the Moon Soul learn to channel their own life energy into chilling bolts of darkness. They teach that meditation can unlock the darkness powers to unleash the indomitable darkness by the soul of every living creature. Monks of the way of the Sun and Moon Soul are at odds with each other often fighting when ever they met though some monks don't mind the other, this is rare between the two.

Shadow Meld

You gain resistance to Necrotic while in magical darkness.

 

Necrotic Moon Bolt

At 3rd level, 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, 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.

Dark Defense

At 6th level, immediately after you take damage from radiant, you can spend 2 ki points to cast the Darkness spell as a bonus action to nullify half of the radiant. While in darkness you gain +2 AC, all radiant damage is nullified within until it is dispersed or the enemy is outside of the area.

You can spend additional ki points to cast Darkness 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.

Chilling Moonburst

At 11th level, as an action, you magically create an orb and hurl it at a point you choose within 150 feet, where it erupts.

Each creature in that 25-foot-radius must succeed on a Constitution saving throw or take 2d8 Necrotic damage. A creature doesn't need to make the save if the creature is behind total cover that is opaque. It remains for 1d4 turns slowing enemies, if anyone is knocked out they automatically fail a death save.  

You can increase the sphere's damage by spending ki points. Each point you spend, to a maximum of 3, increases the damage by 2d8.

Moon Shield

At 17th level, you shed Darkness in a 30-foot radius and dim light for an additional 30 feet. You can dissipate or restore the darkness as a bonus action.

If a creature hits you with a melee attack while this darkness surrounds you, you can use your reaction to deal necrotic damage to the creature. The necrotic damage equals 6 + your Wisdom modifier.