Monks that walk the way of the Oni were once so utterly wicked that their souls are beyond any redemption and have started to transform into an Oni. These Monks have decided to embrace this transformation and use their power however they see fit.

You can choose the origin of your Oni Curse or determine it by rolling on the Origin of the Oni table. Roll a d4  to decide 

1.  You killed your loving family in order to start a new life with your mistress
2. You use to bath in the blood of innocents 
3. You sold your soul to a night hag in order to gain riches 
4. You stole from the rich and poor alike not caring who you stepped on to get what you wanted 

Weapon of an Oni

When you choose this tradition at 3rd level, you gain access to the Oni weapon of choice, the Kanabo this weapon can only be used by you. You are proficient with the Kanabo and count as a monk weapon. The Kanabo deals two rolls equal to two rolls of your Martial Arts die in bludgeoning damage. While the Kanabo is in your possession you can't be disarmed unless you are incapacitated. If it is on the same plane of existence, you can summon your Kanabo as a bonus action on your turn, causing it to teleport instantly to your hand.

Oni's Reaction

At 3rd-level you have become closer to becoming an Oni. If a creature you can see within 10 feet of you hits you with an attack roll, you can spend 1 ki point to use your reaction to block the attack with your Kanabo and roll one of your Martial art dice, applying a bonus to your AC equal to the number rolled, potentially causing the attack to miss you.

Kanabo Improvement

At 6th level, you extend your ki into your Kanabo, granting you the following benefits:

• Your attacks with your Kanabo weapons count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage.
• Once on each of your turns when you attack with your Kanabo using the Attack action, you can make one additional unarmed strike attack as part of the same action.
• If you use your stunning strike feature, while attacking with your Kanabo, the target has disadvantage on the saving throw.

Blood of the Oni

At 6th level, you gain the blood of an Oni, granting you the Oni’s regenerative ability. Once on each of your turns, you can reduce your speed by 10 ft until the end of your turn and roll a Martial Arts die. You regain a number of hit points equal to the number rolled plus your proficiency bonus.

Heightened Abilities

At 11th level, your body starts to change and grow in power as you get used to the Oni blood running through your body. Once on each of your turns when you miss an attack with your Kanabo you can spend 1 ki point to use your reaction to try and hit the same target with your Kanabo, roll one of your Martial art dice, applying a bonus to your attack roll equal to the number rolled, potentially causing the attack to hit that target.

Additionally, you gain blindsight with a range of 10 feet. You can spend 1 ki point to increase this range to 120 ft until the start of your next turn.

The Oni

At 17th level, you have permanently been changed into an Oni, growing in size. If you are smaller than Large, you become Large, your reach increases by 5 feet. You are now counted as Giant, and whenever you roll a martial art die, you can roll additional martial art die with it. Your Dexterity and Wisdom scores increase by 2. Your maximum for those scores is now 22.