Way of the Demon Fist

Many monks achieve perfection of the body through use of martial arts and self-discipline, but for those that follow the way of the Demon Fist this is not the case. to go this way offers power to destroy, to degrade, to ransack. Many who obtain this power do so by accepting the energy of a demon or other similar form of evil and seek to channel it into their body, adopting it as their own. This power can also be forced onto an unwilling creature, afflicting them with unwanted destructive desires. They can then use this power given to them by channeling it through their fists and turning their bodies into a literal weapon, which causes havoc upon a person's health and state of mind. Their Ki is also represented as a dark energy that flows through their body like water, which can take visible form over the monk like an aura. The colors of the aura can vary, but the two most common are green and black. This path is considered forbidden as it is purely destructive in nature, and not a true representation of a monk's true ideals of practice, self-control, and discipline. Many in the Demon Fist will also have a hard time keeping from giving into their destructive nature, meaning that many will find such power more a burden or a curse. 

Cursed Energy

When you choose this path at 3rd level, your body begins to secrete evil energy at will. When making unarmed attacks, you may choose between necrotic and bludgeoning damage. If you deal necrotic damage this way, it also reduces the hit point maximum of the creature. This lasts for 24 hours, or if removed by the remove curse spell. 

Demonic Destruction

You may spend 2 ki points. If you do so, each time you roll necrotic damage and get the highest number on the die, you may roll another damage die of the same type and add it to the damage. This last until the end of your turn. 

Corrupted Ki

When you use Step of the Wind, you may spend an additional ki point to gain a flying speed of 30ft until the end of your turn as wings made of green or black energy temporarily sprout from your back, carrying you forth. 

When you use Patient Defense and a creature misses you with an attack, you may use a ki point to force the creature to make a wisdom saving throw against your Ki save. On a failure, they act as if under the effects of the Confusion spell as your evil infests their mind, causing them to act irrationally from a power they aren't used to. 

When you successfully use deflect missiles to attack the opponent with a projectile, you may force them to make a constitution saving throw. On a failure, they are poisoned. 

Manifest Sins

Your darkness forms into a weapon that represents your personality for 2 Ki points last for 1 minute. This weapon attack is 1d8 + DEX modifier + WIS modifier and deals damage equal to your unarmed strikes (note damage from this weapon cannot be blocked or infective) + 1d4 necrotic damage. Add one dice for every two levels above 6th

Essence of the Archdemon

At 17th level you have reached the peak of your control over the destructive forces you obtained, having now mastered and achieved absolute ownership over the energy, firmly established as a part of you. You may spend five Ki points to activate your destructive Aura. This last for a minute, or until you cause it to end with a bonus action.

You are considered a fiend. 

You may choose any number of creatures within 30ft of you. They have disadvantage on constitution saving throws. 

Your necrotic damage ignores resistance and immunity. 

You have resistance to non-magical bludgeoning, piercing, and slashing damage.