Your monk training has included exercises that many would consider extreme and brutal. The training has included many months of starvation, dehydration and endless mundane task.  

Fists of Exhaustion

-Starting when you choose this tradition at 3rd level, when you hit with a Flurry of Blow attack you can attempt to chill the enemy. The target must make a constitution saving throw. On a failure it's speed is reduced to 0. On a successful save it's speed is reduced by 10 feet. 

- Instead of trying to reduced your targets speed you can Spend 2 Ki points to have the target make a Constitution saving throw. On a failure the target takes 1d8+Monk level in Necrotic Damage and suffers 1 level of Exhaustion. On a successful save the target takes no additional damage and doesn't suffer any levels of exhaustion. This attack can't give exhaustion if it would cause the target to have 6 levels of exhaustion.

Unrelenting Endurance.

At 6th level you gain proficiency on constitution saving throws. At 15th level you double your proficiency bonus when making a constitution saving throw.

You gain the Timeless Body Feature. 

You can't gain exhaustion.

Hardened Skin

At 11th level Choose one:

-You gain Resistance to Cold damage.

-You gain Resistance to Fire damage.

You also gain Resistance to Necrotic Damage and do not suffer any negative effects that weather effects inflict. 

 

Last Breath

At 17th level when you hit a creature with 3 or more levels of exhaustion you can have the life force of the creature vanish as it grows tired.

When you hit a creature with 3 or more levels of exhaustion you can choose to inflict additional 10d10 Necrotic Damage to the target.

When you hit a creature with 2 or more levels of exhaustion you can choose to inflict additional 5d10 Necrotic Damage to the target.

You can use both of these features once per long rest.