The forces of the lower planes – demons, devils, and their ilk – are a target of scorn by all who tread the path of inquisition. However, some believe strongly in the ideal of fighting fire with fire; that to defeat a fiend, one must use their own powers against them.

Monks from the Way of the Demon Hunter have undergone a transformation that infuses fiendish essence in their own being. Their methods of obtaining this power varies between individuals; some imbibe a concoction of demon's blood, others perform risk-laden dark rituals and have survived by some miracle, or have even dared to enter a pact with a demon or devil, only to break their oath the moment their power has been obtained. All fiends scorn such thieves of their power, and will hunt them relentlessly.

Regardless the method, those of the Way of the Demon Hunter are looked upon with a special disdain due to its. However, since its founding, many fiends have fallen to the these maverick warriors; their methods are hard to dispute.

Fiendish Boons

Starting at 3rd level, you are imbued with the supernatural powers of a fiend. Choose one of the boons from this list. At 7th, 11th, and 15th level, you can choose another ability from this list to learn.

You may use fiendish boons from this list a number of times equal to 1 + your Wisdom modifier. Your uses are recovered after a long rest.

If your boon require a saving throw, the DC equals 8 + your proficiency bonus + your Wisdom modifier.

Any damage done by your demonic boons ignores the resistances and immunity of fiends.

Burning Gaze 

As a bonus action, you shoot a beam of fire from your eyes that sears all in a line. All creatures in a 5-foot wide, 15-foot long line originating from your position must make a Dexterity saving throw or take 2d8 fire damage.

The fire damage increases to 4d8 at 7th level, 6d8 at 11th level, and 8d8 at 17th level.

Demonic Sigil

You may cast glyph of warding at 3rd level without requiring material components. If you choose to use the Spell Glyph option, you may use silence, fear, or web for the glyph as if you had them prepared.

The spell level you cast glyph of warding at increases to 4th at 7th level, 5th at 11th level, and 6th at 17th level. 

Fel Wings

Your infused powers enable you to grow fiendish wings from your back. Your long and high jump distance is doubled and you may use your wings to reduce your rate of falling to 60 feet a round, as per the feather fall spell. You lose these features if you are unable to move.

Fiendish Charge

As an action, you extrude a burning aura and rush in a straight line up to your movement speed towards a free space, phasing through any creatures as you do without provoking opportunity attacks. Each creature that you phase through takes 3 fire damage.

While moving, you may make melee weapon attacks against any creature within 5 feet of yourself. You may attack as many times as you would be able to using the Attack action, and may use your bonus action to attack with two-weapon fighting or flurry of blows. You may attack the same creature multiple times or split your attacks against multiple targets.

Glaive Throwing

Warglaives wielded by you gain the Thrown property with a normal range of 20 feet and a long range of 60 feet. Immediately after the attack, the warglaive flies back to your hand.

Helldive

As a bonus action, you leap in the air up to your maximum high jump distance and move to a free space within 10 feet. As you land, you unleash a shockwave that pulses with hellfire and shakes the ground beneath you. All creatures standing within 5 feet of the space you land on must make a Dexterity saving throw. A target takes 1d6 fire damage and 1d6 force damage, and is knocked prone on a failed save, or half damage and is not knocked prone on a successful one. 

The damage of both the force and fire damage increases to 2d6 at 7th level, 3d6 at 11th level, and 4d6 at 17th level.

Infernal Aura

As a bonus action, you wreathe yourself in green flames that emanate from your body. All creatures that move into or start their turn within 5 feet of you takes fire damage equal to half your monk level. The aura lasts for one minute before dissipating. 

Warglaive Proficiency

At 3rd level, you gain proficiency with warglaives, which count as monk weapons for you. When you make a melee attack on your turn with a warglaive, it gains the light property for that attack.

WARGLAIVE
melee weapon (martial, sword)

The warglaive is a multi-bladed edged weapon used by certain groups of elite elven warriors. They are fierce, fast weapons in skillful hands.
Cost: 25 gp
Damage: 1d8
Damage Type: slashing
Properties: finesse
Weight: 3 lb.

Spectral Sight

Starting at 6th level, your eyes glow with a fiendish flame, heightening your senses and allowing you to easily detect the taint of nearby fiends. You have advantage on Wisdom (Perception) and Wisdom (Insight) checks when attempting to detect creatures of the fiend type.

In addition, as a bonus action, you may immediately gain blindsight to a range of 60 feet. Creatures you detect with this blindsight appear as a fiery glowing silhouette of their physical appearance and you see the silhouette of a shapeshifted fiend in its true form. This feature lasts for 1 hour. Once you’ve used this feature, you cannot do so again until you take a short or long rest.

Demonic Wards

Starting at 11th level, you can channel the power of the Lower Planes to ward off extraplanar threats by using magical, warding tattoos that you inscribe on your body. You have advantage on saving throws against spells and other magical effects from fiends. In addition, you may cast the absorb elements spell when you take acid, cold, fire, lightning, or thunder damage from fiends.

Metamorphosis

Starting at 17th level, your mastery over your powers allow you to assume the form of a fiend. You become a visage of unbridled strength; your muscles bulge and your body is covered with spiked growths.

• You gain 50 temporary hit points. If any of these remain when the Metamorphosis ends, they are lost.
• If you take the Attack action on your turn, you can make one additional melee attack as part of that action.
• When a creature within 5 feet damages you with a melee weapon attack, they take 1d8 piercing damage.
• Your movement increases by 30 feet.
• You may cast fire bolt at-will using Wisdom as your spellcasting modifier.

This form lasts for 1 minute, or until you fall unconscious. Once you use this feature, you cannot do so again until you finish a long rest.