The Cinder King — Sagor från Valoris

No one who takes this pact is ever given a name. There is only the fire — banked low behind some wall at the edge of thought, old beyond reckoning, and patient in a way that nothing merely hungry could be. It does not rage. It waits. And it speaks to those who will listen: in warmth against the back of the neck, in light behind closed eyes, offering more of itself for very little in return. Only that you carry a coal of it out into the world. Only that you keep it burning.

Warlocks of the Cinder King come to their power gently, and that is the danger in it. The fire is generous; it asks for nothing that feels like a price. But those who serve longest begin to notice that the heat answers faster than it used to — as though, on the far side of that wall, something has been leaning slowly closer.

“I thought I had found a hearth to warm my hands at. I had my hand on a door.”

Attributed to the last of the ember-sworn

The Pact

Warlock Level	Feature
3rd	Cinder King Spells, Feed the Flame
6th	Drink the Fire
10th	Cinder Heart
14th	Open the Seam

Cinder King Spells

Warlock Level	Always-Prepared Spells
3rd	Burning Hands, Hellish Rebuke
5th	Scorching Ray, Flaming Sphere
7th	Fireball, Melf's Minute Meteors
9th	Wall of Fire, Fire Shield

Level 3

Feed the Flame

The fire grows by consuming, and it shares the meal. When a creature is reduced to 0 hit points within 10 feet of you, you gain Temporary Hit Points equal to your Charisma modifier + your warlock level (minimum of 1).

And the fire you carry is older than this world's: colder things cannot easily turn it aside. The fire damage you deal ignores Resistance to fire damage.

Level 6

Drink the Fire

You have Resistance to fire damage. When you would take fire damage, you can use your Reaction to draw it in instead: you take none of that damage, and the next time you deal fire damage before the end of your next turn, it deals extra damage equal to the amount you prevented, up to a maximum of your warlock level.

You can use this Reaction a number of times equal to your Charisma modifier (minimum of once), and you regain all uses when you finish a Long Rest.

Level 10

Cinder Heart

You are immune to fire damage. When damage reduces you to 0 hit points but doesn't kill you outright, you can drop to 1 hit point instead and erupt: each other creature within 15 feet of you makes a Dexterity saving throw against your spell save DC, taking fire damage equal to your warlock level on a failed save, or half as much on a success. This fire ignores Resistance and Immunity to fire.

Once you erupt this way, you can't do so again until you finish a Long Rest.

For a single heartbeat, those near you feel a heat that does not belong to this world.

Level 14

Open the Seam

As a Magic action, you tear a seam in the world at a point you can see within 90 feet, and a place of endless fire pours through. A 20-foot-radius, 40-foot-tall Cylinder of otherworldly flame roars into being there and burns for 1 minute.

When the seam opens, and whenever a creature enters the Cylinder or ends its turn there, that creature makes a Dexterity saving throw against your spell save DC, taking 6d6 fire damage on a failure or half as much on a success. This fire ignores Resistance and Immunity to fire, and its glare leaves the area Heavily Obscured to creatures outside it.

Once you use this feature, you can't do so again until you finish a Long Rest, unless you expend a Pact Magic spell slot to use it again.

Any creature that looks into the seam glimpses a country wholly aflame, and a shape standing at its heart. None of them, afterward, remember having seen it.