Way of the Inevitable

Wrathful Rose
At 3rd level, you can begin a stance that brings both you and and your foe closer to the end. As a bonus action, you can expend 1 ki point, as well as take psychic damage equal to your level (this damage cannot be reduced), to enter this stance for 1 minute. While in this stance, anytime a creature targets you with a melee attack, you can use your reaction to make an attack against that creature.

Gravekeeper
At 6th level, you see the opportunity of life as well as death. Whenever you reduce a creature to 0 hit points or score a critical hit, your next attack is made with advantage and you deal an additional martial arts die of necrotic damage. Additionally, the first time each round you regain hit points, you regain an additional amount of hit points equal to your martial arts die.

Cycle of Thorns
At 11th level, your speed and precision at which you return blows is unparalleled. When you use Wrathful Rose’s ability to attack as a reaction, you can instead attack twice. Additionally, creatures that hit you with a melee attack take piercing damage equal to your martial arts die while in Wrathful Rose’s stance. This damage is treated as magical for purposes of overcoming damage resistance.

Beauty of the End
At 17th level, you learn the true ideal of purpose over existence. As an action, you can declare one creature within 60 feet of you to contest in a battle of will for one minute. At the beginning of each of their turns, they must make a Wisdom saving throw (DC = 8 + your proficiency bonus + your Wisdom modifier) at disadvantage. On a failure, they take 3d10 psychic damage. If they succeed, you take the damage instead.