Hellsworn

When speaking of Hellsworn, one thing must be made absolutely clear: despite their similarities in combat, and their devotion to a higher power, Hellsworn are not paladins.  Rather, they are the product of unholy power passed down from a being of the underworld.  In truth, they have more in common with warlocks in terms of how they acquire their powers. But whereas a warlock makes a pact with a higher power, Hellsworn are that power, or can at least act as a legal intermediary, able to make such contracts themselves.

When individuals try to back out of their deal and hide from those seeking to collect, Hellsworn are sent to find them and claim what is rightfully their benefactor's.  But there is another purpose to one who would swear their allegiance to a lord of Hell. Most Hellsworn have resigned themselves to the reality that, upon their death, they will find themselves plunging into the River Styx, where they will emerge as a lemure - the smallest, weakest, lowest ranked devils in all of the Nine Hells. Theirs is a pathetic existence, and only through direct interference with a devil of higher rankings will a lemure emerge from the river as a lesser devil, ready to begin the long process of climbing the ranks of devilkind. 

But they have made a bargain. Each soul they claim for their master, be it collecting from those who've made a contract or by making a contract with them yourself, are all accumulated like currency.  They are promised that, upon their death, the souls of those they harvested will be tallied up and used to secure them a quick promotion upon arriving Avernus.

For those facing certain damnation already, this is too good of a deal to pass up.  For those who have angered an archdevil, they are too big a threat to ignore. And so, the Hellsworn forge a pact with one of the lords of Hell, pledging their service to avoid the pitiful existence of a lemure, and beginning their ascension through the hierarchy of the Nine Hells.

Oath Spells

You know the control flames and produce flame cantrips. Optional hellish spells have been added to the list of spells you may prepare from the paladin spell list. You also gain oath spells at the paladin levels listed in the Hellsworn Spells table. See the Sacred Oath class feature for how oath spells work. 

Hellsworn Spells

Bonus Proficiencies

You gain proficiency with Calligrapher's Supplies and the Viol.

 Additionally, you gain proficiency with one of the following skills: Deception, Insight, Intimidation, Performance, or Persuasion.

Twisted Soul

At 3rd-level, your contract twists your mind, body, and soul with hellish influence.  You can read, speak, and write both Abyssal and Infernal.

Your spells or abilities which would deal radiant or fire damage, such as Divine Smite or wall of fire, instead deal your choice of fire or necrotic damage, chosen each time you cast or activate it. Your Divine Smite class feature deals it's bonus damage to celestials and fey instead of fiends and undead.

You have devil sight, allowing you to see normally in darkness, both regular and magical, out to a range of 120 feet. 

Channel Divinity

When you take this oath at 3rd level, you gain new options for Channel Divinity, as seen below. See the Sacred Oath class feature for how Channel Divinity works.

Also, you may refer to "Channel Divinity" in sarcastic terms, as it is very clearly not divine.  Or perhaps you refer to it as something else. Think about what circle of the Nine Hells your power comes from.  Is it from Asmodeus himself? If so, consider something like "Channel Nessus", referencing the circle of the Nine Hells that he presides over.  Or perhaps something more vague, such as "Channel Dread".  It's all flavor, so as long as nobody else in your game is confused it should be fine. 

Conjure Hellfire.  As a bonus action, you can imbue one weapon you are holding with hellfire, magical shadows wreathed with flames, by using your Channel Divinity. For 1 minute, this weapon deals additional fire or necrotic damage equal to your Charisma modifier (with a minimum bonus of +1). You choose the type of damage it deals each time you activate this ability. The weapon also emits bright light in a 10-foot radius and dim light 10 feet beyond that. If the weapon is not already magical, it becomes magical for the duration. 

As an action, you may dispel this flame by slamming your weapon into the ground, creating a line of fire 30-feet long and 5-feet wide. Creatures caught in it's path must make a successful Dexterity saving throw or take an amount of d8's in fire or necrotic damage equal to your proficiency bonus. On a successful save they only take half damage.

If you are no longer holding or carrying this weapon, fall unconscious, or choose to end it, then this effect ends.

Infernal Contract.  As an action, you may use your Channel Divinity to make a magical contract between yourself and another willing player character.  If you do so, you each gain a boon. A contract lasts until you use this Channel Divinity ability again to replace it with a new one, at which point the old contract is engulfed in hellfire and turns to ash. Only one contract may be active at a time when you take this archetype at 3rd-level, and you can make an additional contract with a different player at 9th- and 18th-level.

You may each take the same benefits from a contract or you may each choose a different boon. Listed below are a few of the different kinds of contracts you could use:

• Grant Me Knowledge. Spellcasters gain a spell slot or pact magic slot at a level of which you can both cast spells from.
• Grant Me Skill. Gain one of the other player character's skill, tool, or weapon proficiencies.
• Grant Me Sight. Gain a sense from the other player character. This includes your devil sight.
• Grant Me Resilience. Gain a resistance from the other player character.
• Grant Me Prowess. Weapon attacks may be made using the Intelligence, Wisdom, or Charisma modifier for attack and damage rolls instead of Strength or Dexterity.

At the DM's option, you may choose an alternative contract effect, but it should be no more powerful than those described above. The DM has final say on such a contract's effect.

Beguiling Aura

Starting at 7th level, your otherworldly presence radiates off of you, distracting those nearby. 

You have advantage on Charisma(Deception) and Charisma (Persuasion) ability checks made against creatures within 10 feet of you. Additionally, any attack made against a friendly creature within 10 feet of you, besides yourself, is made with disadvantage.  Neither ability can effect a creature who is unable to see you.

At 18th level, the range of this aura increases to 30 feet.

The Devil You Know

Also at 7th level, you take on aspects of a fiend, growing resilient to physical attacks.  Any time you would take bludgeoning, piercing, or slashing damage, you reduce the damage taken by an amount equal to your Charisma modifier. 

Additionally, you can use a bonus action to sprout large, leathery wings, granting you a flying speed equal to your walking speed for up to 1 minute. Once you've used this ability, you may not do so again until after taking a short or long rest.

Hellgate

At 15th-level, you may use the power of your contract to pull you and your allies through the Hells itself, potentially putting you in a more advantageous position. As a bonus action, you and any number of willing, friendly creatures within 15 feet of you are instantly teleported to a position you can see up to 30 feet away.  Any hostile creatures within 15 feet of you at either location must make a successful Dexterity saving throw, taking 4d8 fire damage on a failed save and half as much on a success.

Some creatures may find this method of transportation disturbing. When you've used this ability once, you may not do so again until you finish a short or long rest.

Fiendish Transformation

At 20th level, you can use your action to undergo a fiendish transformation. For 1 hour, you gain the following benefits:

• You are immune to fire, cold, and poison damage, cannot be poisoned, and are resistant to bludgeoning, piercing, and slashing damage.
• When you take the Attack action on your turn, you can make one additional attack as part of that action.  
• Your melee weapon attacks score a critical hit on a roll of 19 or 20 on the d20.

Once you use this feature, you can’t use it again until you finish a long rest.