Hellfire Knight

Those who walk the path of the Hellfire knight have embraced the fiery passion of battle.  Channeling it into their very being.  Some use it as light to lead others, while others use it as a force of destructive power to rend their foes.  One thing they all have in common is the passion they have for battle.

Fiery Strikes

Starting at 3rd level, you use a bonus action to imbue your attacks with the heat of battle.  All of your attacks deal an additional d4 fire damage for 1 hour, you also gain resistance to fire and disease for the duration.  The d4 gets replaced by a d6 at 10th level, then replaced by a d8 at 14th level, and finally a d10 at 18th level.  you can use this feature as many times as your proficiency modifier per long rest.  Gaining any and all expended uses on a long rest.

Fiery Soul

Starting at 7th level when you are reduced to 0 hit points you can instead drop to 1 point.  When you use this feature you generate a fiery explosion centered on you that has a radius of 15 feet.  All creatures within this radius must make a dexterity saving throw vs 8 + your Proficiency + your constitution modifier.  On a failed save they take 4d8 fire damage and half as much on a successful save.  You can not use this feature again until you finish a long rest.

Burning Bright

Starting at 10th level, the flames inside you emits a light in a 30ft radius.  You can suppress this light in a 30ft radius.

Exalted Fire

Starting at 15th level, you are hot to the touch, and gain a permanent immunity to fire damage. You also gai the ability to cast Heat Metal at will.

Walking Inferno

Your mere presence burns those who come across you. While Fiery Strikes is active, you can increase the firepower of your attacks. After using this feature with your bonus action, for 1 minute, all weapon attacks you make deal 10d10 extra fire damage, and ignores resistances and immunities.

Hellish Supernova

You cause a supernova of fire to burn everything around you. All objects in a 60ft sphere, centered around you, turns to ash, and all creatures must make a dexterity save (dc:22). On a failed save, the creatures take 10d12, or half as much on a successful one. Any ally creatures are immune to this blast, and all enemy creatures must make a wisdom save (dc:18) or travel through the nine hells taking an extra 4d8 psychic damage and 5d8 force damage. Fiends are immune to the psychic damage, but still take force damage. This also ignores immunities and resistances. If a creature is blinded AND deafened, they are immune to the psychic damage.