Like a boulder standing unmoved as the water parts around it, Monks of the Way of the Boulder are true bulwarks, absorbing blows so that their allies do not. Boulder Monks condition their bodies until they become like iron, whether they accumulate muscle or fat, the defining trait of a Boulder Monk is always their ability to tough it out.

Their training includes meditating under waterfalls, punching sheets of metal, and consuming plenty of protein. Monks of the Way of the Boulder tend to have a love for life, particularly food and drink, and are just as comfortable engaging in some sporting roughhousing as they are in life and death situations.

Be like rock

When you choose this tradition at 3rd level, your conditioning allows you to focus your ki into your core, allowing you to tense your body and absorb more powerful blows. As a bonus action you can spend 1 ki point to become resistant to bludgeoning, piercing and slashing damage until the beginning of your next turn. Additionally, while in this stance you have advantage on Strength saving throws.

Forward momentum

Also at 3rd level, when you hit a large or smaller creature with an unarmed strike you can force it to make a strength saving throwing or be pushed up to 15ft away from you.

Stonewall stance

At 6th level you can use a reaction in response to being targeted with an attack to spend 1 ki point to allow you to add your constitution modifier to your armour class until the beginning of your next turn. Additionally, you gain temporary hit points equal to your wisdom modifier.

Waterfall meditation

Your many hours of meditation in inhospitable places has given you unmatched vitality. At 11th level when you use Be like rock you now gain resistance to all damage types.

Breathe deep

Also at 11th level you can use a bonus action to spend 2 ki points to heal 2d8+your wisdom modifier. If you took damage this turn then you treat one of the die as having rolled its max value.

Immovable object

You have become a bulwark against your enemies. At 17th level you can use a bonus action to spend 3 ki points to activate Be like rock for 1 minute. During this time, whenever an enemy hits you with an attack you can immediately use your reaction to attack them.