Way of Falling Sand

A martial art in which the user's limbs move in time as well as space, allowing them to go back in time and punch the opponent repeatedly so that the opponent feels the effects of past blows while standing in front of the apparently motionless Déjà Fu practitioner. Similar tricks can be used to render the opponent's attacks ineffective or otherwise incapacitate him. It is best described as "the feeling that you have been kicked in the head this way before". - Terry Pratchett

Deja-Fu

Starting when you choose this tradition at 3rd level, you learn a new form of martial arts based on stealing small increments of time from your opponents, directing the flow of battle by directing time itself.

When you hit an enemy with a melee attack, you may steal a portion of the attacker's time. That creature's initiative score is reduced by a number equal to your Wisdom modifier. If that creature's initiative score is reduced to 0 or below it must make a Wisdom Saving throw or be Slowed (as per the Slow spell) until the end of your next turn. If that creature's initiative score would be reduced beneath 0 it takes its turn at an initiative of 0 this round, then its initiative score is reset to 20 before reducing it further. This cannot cause the a creature to have two turns in one round, or lose a turn in a round.

Thief of Time

At the 6th level you have learned how to manipulate other creature's flow of time, increasing the speed of their personal flow or cutting it off entirely.

Once per turn after you successfully hit a creature with a monk weapon, you may spend 2 ki points to attempt to freeze in time by casting Hold Person.

Additionally, as an action you can spend 3 ki points to cast the Haste spell.

The Thing About Time Travel "People assume that time is a strict progression of cause to effect, but actually — from a non-linear, non-subjective viewpoint — it's more like a big ball of wibbly-wobbly... timey-wimey... stuff." - The Doctor Don't question the logic of time travel and its rules outlined here. Also, don't think too hard about the consequences of messing with time. History and Destiny have a momentum that isn't going to be stopped by one puny Chronalmancer.

Tock, Tick

At 11th level, you have discovered the dangerous art of establishing anchors in the stream of your own time, allowing you to revert to a state of being in your past.

As an action you may spend 5 ki points to set an anchor in time. At the beginning of your next turn, your body will reappear in an unoccupied space closest to the anchor. Then you regain all hitpoints you lost during that time, and any conditions affect you are removed.

This ability, if used creatively, can allow a lot of wacky stuff to happen. It's up to your DM to decide how a few of these things resolve. Interpretation of time travel's effects vary! Additionally, this ability only restores hitpoints and removes conditions. It does not grant additional uses of features, magic items, or other resources.

Chronalmancer

When you reach the 17th level, you mastery over time surpasses even archmages and history's greatest wizards. You are able to remove yourself from time's flow, becoming able to move freely among it.

Once per Long Rest, you may spend 9 ki points to cast Time Stop.