Shadow Arts
At 3rd level, as an action, you can spend 2 ki points to cast Darkness, Darkvision, Pass Without Trace, or Silence, without providing material components. Additionally, you gain the Minor Illusion cantrip if you don't already know it.
Shadow Step
At 6th level, 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.
Cloak of Shadows
By 11th level, when you are in an area of dim light or darkness, you can use your action to become invisible. You remain invisible until you make an attack, cast a spell, or are in an area of bright light.
Opportunist
At 17th level, whenever a creature within 5 feet of you is hit by an attack made by a creature other than you, you can use your reaction to make a melee attack against that creature.