The Way of the Emperor subclass for Monks is inspired by the Star Emperor from the MMORPG Ragnarok Online.

The sun, the moon, and the stars speak to you in the voiceless language of cycles. The natural flow of the seasons tugs at your blood as the tide acts upon the oceans, pushing and pulling with gentle insistence regardless of the storm’s fury, the dragon’s flight, or the antics of otherworldly primordials. Just as the constellations move around the sky in a steady, imperturbable cadence, your will is strong and unshakable, tied to energies that can outlast all others. You can only choose this path at 1st level

 

Solar, Lunar and Stellar Cycle

Starting at 1st level, after finishing a short or long rest, you choose a cosmic phase to attune from those listed below to gain its benefits. The benefits of each cosmic phase are only in effect while you are conscious; if you become unconscious or die, the benefits stop functioning until you regain consciousness.

Any time you are damaged by a critical attack or dropped to 0 hit points, your cosmic phase immediately changes to the next highest numbered phase.

1 - Solar

2 - Lunar

3 - Stellar

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• Example if you were damaged by a critical attack while in the Lunar phase, you would immediately transition to the Stellar phase, or back to the Solar phase if currently in the Stellar phase

 

Additionally, any time you spend Ki points, you can choose to transition to the next highest-numbered phase after resolving the effects of the action used to spend the Ki points; You can use this feature a number of times equal to your Wisdom modifier (minimum of 1), you regain all your uses after a long rest. Use your Ki save DC for every situation a feature from this subclass ask for a saving throw.

Comfort in the Sun, Moon & Stars

You have learned to be at ease when attuned to the sun, the moon, and the stars, and discovered that is not only a feeling but a powerful state of mind that can either drive you if not careful or be used when practiced. Starting at 2nd level, you can add half your proficiency bonus (rounded down) to skills associated with your current Solar, Lunar and Stellar Cycle phase.

If you move into a new Solar, Lunar and Stellar Cycle phase the previous benefits are lost.

Solar

Intimidation and Athletics  checks.

Lunar

Deception  and Stealth  checks.

Stellar

Persuasion  and Insight  checks.

Document of the Cosmic Bodies

To become one with the universe, the Way of the Emperor monk has opted to study the power of the cosmic bodies and literally wield it with their fists, and feet, along with advancing their knowledge.

At 3rd level, you gain proficiency in the Navigator's Tools if you don’t already have it. You can also use Strength instead of Dexterity when calculating your AC for Unarmored Defense.

Warmth of the Sun, Moon & Stars

The sun, the moon, and the stars envelop you in the voiceless language of cosmos providing you with protection. At 3rd level you gain more benefits when attuned to certain phases as described below.

If you move into a new Solar, Lunar and Stellar Cycle phase the previous benefits are lost.

Solar

You gain resistance to Fire damage.

Any time an enemy within 5 feet of you takes damage (by you or anyone else) as a reaction you can choose to deal additional fire damage equal to your Strength modifier; You can spend 1 Ki point to deal twice your Strength modifier, at 11th level it deals 3 times you Strength modifier and at 17th level it deals 4 times your Strength modifier.

Lunar

You gain resistance to Radiant damage.

As a reaction you can enter Patient defense without spending Ki points; You can also use Ki points to gain 1 AC per Ki point used until the start of your next turn.

Stellar

You gain resistance to Psychic damage.

Whenever an enemy’s attack misses you, as a reaction you can teleport a distance of 5 feet; Additionally you can spend 1 Ki point to increase the teleport distance to 10 feet, this feature's distance increases by an additional 5 feet at level 6, 11, 17.

Anger of the Sun, Moon & Stars

Once you reach 6th level, you also have access to a spell based on your current phase, these spells cannot damage you and are casted centered on yourself if they can hit multiple creatures.

Also Your attacks with unarmed strikes count as the types below based on the phase you are attuned for the purpose of overcoming resistance and immunity to nonmagical attacks and damage; if a magic item offers a property based bonus for unarmed strikes the DM chooses the effect priority.

If you move into a new Solar, Lunar and Stellar Cycle phase the previous benefits are lost, but if you can keep concentration on the spell it functions as a normal spell would.

Solar Burst (Solar)

Your unarmed strikes count as Fire property.

You can spend 2 Ki points to cast Flaming Sphere as an action. The sphere will follow your movement while attuned to this phase, otherwise it works as described in the spell.

Light of the Moon (Lunar)

Your unarmed strikes count as Radiant property.

You can Spend 3 Ki points to cast Moonbeam as an action. The beam will follow your movement while attuned to this phase, otherwise it works as described in the spell.

Flash (Stellar)

Your unarmed strikes count as Psychic property.

You can spend 3 Ki points to cast Mind Spike as an action.

Blessings of the Sun, Moon & Stars

Beginning at 11th level, as a action at the end of your turn, you may spend 3 Ki points as if you were casting a concentration spell to move into a Solar, Lunar and Stellar Cycle phase of your choice. If you maintain concentration by the start of your next turn, you move into your chosen Solar, Lunar and Stellar cycle dealing 2d12 + your Wisdom modifier of force damage to enemies in a 10 foot radius around you and gain the benefits of the chosen phase listed below. You must finish a long rest before you can use this feature again.

If you move into a new Solar, Lunar and Stellar Cycle phase the previous benefits are lost.

Solar Flare (Solar)

Arc of sunlight formed by the heat erupts on your body and around you. For one minute, you gain a flying speed equal your current speed. At the end of your movement, each creature within 5 feet of you takes 1d4 fire and 1d4 radiant damage.

New Moon (Lunar)

A bright pale white light surrounds your form. For one minute, At the end of your movement, each creature in a 10 feet sphere must make a Wisdom saving throw; The target is Blinded on a failed save, or Immune to the effects for 24 hours on a success.

Cloak of Stars (Stellar)

You are surrounded by swirling starry motes of light. For one minute, as a movement action you gain the ability to teleport at a distance equal to your current speed.

Emperor of the Sun, Moon & Stars

At 17th level, you can spend Ki points as an action to gain a benefit based on your current Solar, Lunar and Stellar Cycle Cycle phase.

If you move into a new Solar, Lunar and Stellar Cycle phase the previous benefits are lost.

Empyreal Radiance (Solar)

(Recharge 5-6) You spend 5 Ki points and you borrow the sun’s radiance creating a 40-foot-high cylinder with a radius equal to 5 feet multiplied by your Wisdom modifier around your current position. Enemies caught inside the area of effect must make a Dexterity saving throw. Creatures have their speed halved, disadvantage on ability checks, attack rolls and saving throws while inside the area on a failed save, or are Prone on a successful save and can only get back up by succeeding on a Constitution saving throw, until start of your turn. You may spend an additional 4 Ki points to impose disadvantage on the saving throw.

Full Moon (Lunar)

(Recharge 5-6) You Spend 5 Ki points and a ray of shimmering moonlight shines down from above to restore hit points of a creature equal to 4d10 + your monk level, or deal 4d10 + your monk level Radiant damage.

Alternatively, if you drop to 0 hit points and don’t die outright, you may spend 4 Ki points as a reaction to drop to 1 hit point instead. This feature works separately from the rechargeable active part; you can only use this once per Solar, Lunar and Stellar Cycle.

Falling Stars (Stellar)

(Recharge 5-6) You Spend 5 Ki points and the stars send shafts of light down upon your foe. You can direct a number of stars equal to your Wisdom modifier(minimum of 1) to descend upon one creature or several within 60 feet of you. Target creature(s) must make a Dexterity saving throw for each star they are the target of. Each star deals 2d8 Psychic damage and grants advantage to the next attack roll made against a target that fails it's save. If a creature is hit by two or more stars, you may spend an additional 4 Ki points to cause that creature to become stunned until the start of your next turn.

Additional Info

Most of the features in this subclass are adapted from 5th Edition take on the Cosmic Sorcerer Bloodline from 4th Edition D&D by these people;

• Sorcerer Origin - Cosmic made by AwesomeJosh on Reddit

• Cosmic Bloodline made by Bonno on DnD Beyond.

If you had a chance to try this subclass and want to send some feedback feel free to email me at cheester97@gmail.com