Monks of the Way of the Open Hand are the ultimate masters of martial arts combat, whether armed or unarmed. They learn techniques to push and trip their opponents, manipulate ki to heal damage to their bodies, and practice advanced meditation that can protect them from harm.

Open Hand Technique

Starting when you choose this tradition at 3rd level, you can manipulate your enemy’s ki when you harness your own. Whenever you hit a creature with one of the attacks granted by your Flurry of Blows, you can impose one of the following effects on that target:

• It must succeed on a Dexterity saving throw or be knocked prone.
• It must make a Strength saving throw. If it fails, you can push it up to 15 feet away from you.
• It can’t take reactions until the end of your next turn.
• It takes the normal damage from your unarmed attack. You can then immediately use your reaction to attempt to grapple the target.

Homebrew Rule: A creature must use its reaction to resist a grapple or an escape (from the grapple) attempt. 

Breath of Life

At 6th level, you have mastered your mind and  body through intense and repetitive training. Your maximum ki points increases by 2. Once per turn, when you use one or more ki points,  you can heal yourself for a number of hit points equals to the amount of ki points spent times your proficiency bonus.

Formless

Beginning at 11th level, you can enter a special meditation that surrounds you with an aura of peace. At the end of a long rest, you gain the effect of a Sanctuary spell that lasts until the start of your next  long rest. This spell effect does not end early as normal only if the attacks or harmful spells you make or cast while warded are considered ki features such as Flurry of Blows, Ki-Fueled Attack, Deflect Missiles or Stunning Strike (with the exception of Focused Aim). The saving throw DC for the spell equals 8 + your Wisdom modifier + your proficiency bonus.

Void Palm

At 17th level, you gain the ability to set up lethal vibrations in someone’s body. When you hit a creature with an unarmed strike, you can spend 3 ki points to renew your Formless feature and start imperceptible vibrations, which last for a number of days equal to your monk level. The vibrations are harmless unless you use your action to end them. To do so, you and the target must be on the same plane of existence. When you use this action, the creature must make a Constitution saving throw. If it fails, it is reduced to 0 hit points. If it succeeds, it takes 10d10 necrotic damage.

You can have only one creature under the effect of this feature at a time  and you can attack this  creature without losing your Formless feature effect. You can choose to end the vibrations harmlessly without using an action. The vibrations end on their own if you fall unconscious.