Monks on the Path of the Souls Shadow learn to manipulate the shadows on and around themselves.
These monks are often confused with those that follow The way of Shadow. Those that follow this path are more akin to trained Spies and Assassins.

As a darker offshoot to The Way of Shadow, The Path of the Souls Shadow is one that many have died through training and isn’t taken lightly.
The Path of the Souls Shadow was originally designed as a way of guarding the lore and knowledge similarly to the Cobalt Soul, however time has passed that responsibility to them, now they are dedicated to weeding out the corrupted within the corruption. They understand that power above such as the kings and lords or emperors of the kingdom often find their way to the top through the use of the criminal underworld, and when a person of power needs to be toppled a monk following this path will cut the cancer from the political criminal underworld before the cobalt soul takes out the visible symbol of that corruption above, thus truly removing the corrupt from power.

Your Ki points are extracted from the black depths of your shadow, effectively manipulating your own shadow, If you run out of Ki you have no shadow at all and cast no shadow on the ground until rested, any stealth checks made without any ki points available are at a disadvantage. Though the pass through shadow ability once learned can be performed as a ritual to gain advantage, or a straight stealth check.

Shadow Manipulation

As an action, In Combat you can spend 2 Ki points to channel the shadows for a number of newly learned Skills.
The arts involved in manipulating your shadow is taxing on all that try, but through dedication and practice you have begun to start to learn how to detach parts of your shadow as though it is a material thing you can use, though at the moment you can only perform minor manipulations. practice and patience brings many rewards.

Shadow Step

At 6th level, you gain the ability to step from one shadow into another. When you are in dim light or darkness, as a bonus action you can teleport up to 60 feet to an unoccupied space you can see that is also in dim light or darkness. You then have advantage on the first melee attack you make before the end of the turn.

One with Shadows

You have Now through this tradition learned to use the Shadows in a skilled way so much so that you can now use them to assist you in combat. by using the shadows to hold, choke, or even protect yourself and your allies.  

Shadowy Assistance.

At 17th level, you can create a shadow duplicate of yourself with half your HP, to assist you in combat. This shadow duplicate costs 3 Ki Points and 1 full action and reduces your movement to 0 for the turn while you separate yourself and your shadow.
Your shadow self is a duplicate of yourself and works as an individual entity. Though it only has 5 Ki points of it's own which if all spent the shadow assistant will disappear leaving you without a shadow to draw Ki from until you have a long rest.

If your shadow is reduced to 0 HP in combat or dispel magic is cast upon it, it will disappear entirely and you can spend a ki point to regain your shadow.