What happens when you lose everything, but still want to fight? When your spirit is so fragmented that you walk in both worlds, almost ceasing to be alive, just stuck with the will to remain on the earth plane, but without running away from death? Well, some believe that this is the way for the ghost walker. This monk came so close to dying physically and spiritually that he was able to walk on the spectral plane, leaving part of his consciousness there and being able to interact and affect the spirits around him freely.

Spectral Call

At the third level, your ki mastery allows you to summon the spirits around you to assist you and your allies. As a bonus action, you can spend 1 ki point to summon nearby spirits. When you do this, each creature of your choice (maximum equal to your Wisdom modifier - minimum 1) that you can see within 20 feet of you receives a bonus on attack rolls and damage equal to your Martial Arts die until your next turn, furthermore, the damage of this bonus becomes either radiant or necrotic (at your choice).

from that call, the spirits will be present until you spend your bonus action to disperse them or 10 minutes pass.

 

Spirits Present: As long as the spirits are present, whenever you hit an attack on an enemy you can use your reaction to recover 1d4 of temporary Ki points.

Two World Walker

Beginning when you choose this tradition at the 3rd level, due to the strong trauma that brought you close to total death, you are now able to feel the souls and intuitions of the people around you. You can add your Wisdom modifier to all social tests with beings that have souls. In addition, you can spend 1 ki point to receive one of the following benefits for 10 minutes:

Night Vision: you can see in total darkness.

Spectral Sounds: you are able to cause spectral sounds in a location within your field of view (up to 120fts).

Astral Reading: you are able to analyze a spiritual trail, receiving advantages in any test related to tracking or finding such a creature, as long as you have contact with any belonging to the creature or have interacted with it for at least 1 minute in the last 24 hours.

Sibilant Camouflage: if the spirits are present, you can mix the shadows by receiving coverage even in places without the necessary provisions, needing only the spirits and low light environment.

Channel the Spectral

When you reach level 6, you can incorporate the spirits around you, being able to receive certain abilities, causing admiration for your allies and despair in the soul of your enemies.
As part of an action, you spend 1 ki point and channel your soul to absorb the spirits around you, getting wrapped in a spectral cloak, in that state you have resistance to necrotic and radiant damage, in addition to gaining resistance in tests against enchantments and immunity to natural or magical fear for 10 minutes. After using this benefit, you need a short or long rest to recover.

Present Spirits: if the spirits are present, you extend this benefit to your (number equal to your wisdom modifier - minimum 1) allies of up to 120 fts.

Spectral Soldiers

At the 11th level, you have entered into communion with the spirits around you, being able to bring them to the earth plane to attack your enemies.

As part of your Flurry of Blows you can spend your reaction to invoke a number of spectra equal to your Wisdom modifier (minimum 1). Each spectrum attacks with its martial die a creature within its melee range and causes radiant or necrotic damage (at your choice).

Spirits Present: if the spirits are present you can use this benefit to protect your allies (a number equal to your Wisdom modifier - minimum 1) up to 120 fts giving them your Martial Arts die to absorb the damage as part of a reaction.

Spectral Guardian

From the 17th level, your connection to the spectral plane is complete, you now walk in both worlds, being able to control almost any spirit. Their unarmed attacks start to cause spectral explosions increasing their range. You can communicate with any spirit and can make it incarnate in weapons and armor, making them special artifacts that amplify your powers.

As part of an action, spend any amount of Ki points to incorporate the artifact (the more, the more benefits).
When an embedded artifact is used by you, you receive the following benefits:

Spectral Leap: You can use jumping between the two worlds to reappear at a location of your choice (similar to the Misty Step spell).

Phantom Elevation: you become almost all incorporeal, being invulnerable to radiant and necrotic damage (natural or magical) and not suffering damage from non-magical attacks.

Phantom Explosion: when you keep your artifact of power, the spirits embodied in it can be released, causing a spectral explosion in all enemies within a radius of 9m. The damage is equal to the amount of Ki remaining on the object x your Martial Arts die.

Keeping the artifact active spends 1 Ki point per turn (used to summon the artifact)

Present Spirits: when the spirits are present you can raise your artifact and provide all allies with an attack roll and damage bonus equal to your Wisdom Modifier + Ki Points spent to summon the artifact.