The Hellfire

The Hellfire is a leader of Clan Hellfire, who's empire is scattered around the world. Unlike warlock patrons such as The Fiend or The Great Old One, you could easily encounter one in a military fort or a castle on the Prime Material Plane. The Hellfire will almost always have a title of nobility such as a Lord or Duke. The leader of Clan Hellfire only gifts patronage to other members of Clan Hellfire, and many Hellfire patrons will have the head Hellfire as their patron. Serving a Hellfire means you gain extra powers, but at a cost. Once a month, you must perform a ritual to convert your blood to liquid fire. This ritual grants full immunity to fire and sustains your body. However, you can't sustain yourself on mortal food, so if you miss a ritual or cannot perform it, your blood will convert back, you will begin losing your warlock powers, and ultimately, you will deteriorate and die. This curse is permanent, even if you cut ties with your patron. The only way to ever be fully released from this pact is to sign a contract with the head of Clan Hellfire, who dabbles in devil contracts. This contract will generally include freedom from the curse in return for ownership of your soul after death.

Ritual of the Hellfire

Once monthly, you must perform a ritual, transforming your blood into liquid fire. This ritual involves a transmutation circle written in blood that fades to ash after the ritual. Performing the ritual involves letting your blood into a specific part of the circle and chanting in Old Infernal. A creature must be willing in order to perform this ritual and the offspring of anyone who takes part in it will be a Hellfire tiefling. The ritual grants immunity to fire, as well as sustenance for a whole month. After the first time a creature performs this ritual, that creature can no longer sustain themselves on mortal food. A creature who stops the ritual will have their blood return to normal. The powers the ritual grants will begin to fade, and their body will ultimately deteriorate. A warlock of The Hellfire who halts this ritual will lose all of their warlock powers until they perform the ritual again, if they last that long without dying. Many warlocks of The Hellfire or Hellfire tieflings will carry vials of this "Fire of Life" with them in case they cannot perform the ritual to sustain them. They will lose the ritual's powers but won't deteriorate or die from starvation.

Hellfire's Rage

Starting at 6th level, you begin to take on qualities of a Hellfire tiefling. You grow small horns from your forehead that grow as your power increases, and a long prehensile tail. Your skin color may begin to change to more of a red, purple, blue, or pale white color. Your eyes become a solid color of black, white, red, silver, or gold, with no visible sclera or pupil. This form is only active in hours of darkness, while you look normal during daylight hours. As an action, you can channel your power into this form causing you to become extremely devil-like in appearance. All creatures within 60 ft. of you that can see you must make a Wisdom save against your spell save DC or become frightened for 1 minute or until you end the effect as a bonus action. Until the effect ends, any creature that looks at you that has not succeeded its save must make the save. A creature that is under this effect may repeat the save at the end of each of its turns, ending the effect on a success.

Wings of the Hellfire

Starting at 10th level, the power of the Hellfire grants you wings while in your devilish form. Your devil form now includes large, leathery, bat-like wings protruding from your back. You have a flying speed of 40 ft. while in this form.

Soul Burn

At 14th level, when you hit a creature with an attack, you can use this ability to directly damage the target's soul. The creature becomes incapacitated until the end of your next turn, and takes 5d10 force and 5d10 psychic damage that is unaffected by resistances or immunities. If the creature is an undead or construct, this instead deals 10d10 force damage. If the creature has signed their soul over to a Hellfire or devil, that creature instantaneously dies and their soul is transported to the Nine Hells. This ability has no affect on devils and deals double damage to demons. 

Once you use this feature, you cannot use it again until you finish a long rest.