Stone Body

When you choose this tradition at 3rd level, your body becomes as tough as mountain stone. While you are wearing no armor and not wielding a shield, you can choose for your AC to equal 10 + your Constitution modifier + your Wisdom modifier.

In addition, you have advantage on saving throws made against being moved or knocked prone.

Boulder's Toughness

Also at 3rd level, you've learned to ignore pain and withstand mortal injury. You can use your reaction to deflect or ignore the force of a blow when you are hit by a melee weapon attack. When you do so, the damage you take is reduced by an amount equal to 1d10 + your Constitution modifier + your monk level.

Unwavering Stance

Starting at 6th level, your strength of body and spirit allows you to remain resolute, even in the middle of a dragon's breath attack or a fireball spell. Whenever you are subjected to an effect that allows you to make a Dexterity saving throw to take half damage, you can choose to make a Constitution saving throw instead.

Mountain Soul

Beginning at 11th level, your soul is infused with the spirit that causes mountains to rise and fall. You can use your ki to duplicate the effects of certain spells. As an action, you can spend 5 ki points to cast bones of the earth*, stone shape, stoneskin, or transmute rock*. Additionally, you learn the mold earth* cantrip if you don't already know it.

* This spell is found in Xanathar's Guide to Everything.

Absolute Resilience

At 17th level, your body is a stone fortress. You gain the following benefits:

• You cannot be forcibly moved or knocked prone unless you allow it.
• You can use your Boulder's Toughness feature to reduce any damage that you take from another creature.
• When you use your Unwavering Stance feature to make a Constitution saving throw instead of a Dexterity saving throw, you take no damage if you succeed on the saving throw, and only half damage if you succeed.