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Under the Dome: The Horned King’s Forbidden Magic

Most necromancers learn to command death.

The Horned King learned to command what comes after.

For centuries, scholars have debated how the ruler of the Bone Caravan achieved his impossible form. Liches bind themselves to phylacteries. Death knights cling to purpose through curse and hatred. Yet the Horned King exists somewhere between those states, sustained by forces neither tradition fully explains.

The answer may lie in the magic he developed during the early years of the apocalypse.

These are not spells found in ordinary grimoires. They are not taught in academies or preserved in guild archives. Both are considered existential threats by most Dome authorities, not simply because of their destructive potential, but because they reveal uncomfortable truths about the relationship between death, chaos, and survival.

If these spells can be mastered, then perhaps the Horned King’s transformation was not unique.

Perhaps it was merely the first successful attempt.

Kingdom of the Last Breath

8th-Level Necromancy

Casting Time: 1 Action

Range: 300 Feet

Components: V, S, M (a fragment of bone from a creature that died willingly)

Duration: Concentration, up to 1 Minute

The Horned King created this spell during the early construction of the Bone Caravan. Witnesses describe the sensation as reality briefly forgetting the difference between life and death.

When cast, a 60-foot-radius sphere appears centered on a point within range. Pale green stormlight fills the area as spectral chains emerge from the ground and connect every creature caught inside.

Hostile creatures entering the area or beginning their turn there must make a Constitution saving throw.

On a failed save, a creature takes 8d8 necrotic damage and cannot regain hit points until the start of its next turn.

On a successful save, the creature takes half damage.

The true terror of the spell is what happens next.

Whenever a creature dies within the area, its remaining vitality is redistributed among the spell’s caster and allied creatures of the caster’s choice within the sphere. Each chosen creature regains 3d8 hit points and gains advantage on its next attack roll or saving throw.

Undead creatures affected by this healing instead gain temporary hit points equal to the amount restored.

Legend claims the Horned King used this spell during the defense of the first Bone Caravan settlement. Entire battalions of undead reportedly fought for days without collapsing as each casualty fueled those still standing.

The spell earned its name from survivors who described the battlefield as a kingdom where every dying breath belonged to the king.

Throne of the Black Engine

9th-Level Necromancy

Casting Time: 1 minute

Range: Self

Components: V, S, M (100 gp worth of Grind, which the spell consumes)

Duration: Concentration, up to 10 minutes

Among all of the Horned King’s creations, none are feared more than the Black Engine. Through forbidden rites and impossible alchemy, fragments of that dreadful machine can be called forth to serve as a throne of conquest and annihilation.

A colossal construct of bone, black iron, soul-fire, and crystallized chaos erupts from the ground beneath you. The throne occupies a 20-foot-square area, rises 40 feet into the air, and can support only you. While seated upon the throne, your speed becomes 0 and you cannot voluntarily leave it. If you leave the throne for any reason, this spell ends immediately.

The throne is a Gargantuan construct with AC 20 and 300 hit points. It is immune to poison, psychic, and necrotic damage. At the start of each of your turns, spectral laborers emerge from hidden furnaces within the throne and repair its structure, restoring 20 hit points. If the throne is destroyed, the spell ends.

While seated upon the throne, you gain the following benefits:

• You gain 150 temporary hit points.

• You have resistance to bludgeoning, piercing, slashing, force, and necrotic damage.

• You have advantage on Constitution saving throws made to maintain concentration.

• Your necromancy spells ignore resistance to necrotic damage.

• You can perceive creatures and objects through nonmagical barriers within 120 feet as though they were transparent. This vision cannot penetrate more than 10 feet of solid material.

• Once per turn when a creature succeeds on a saving throw against one of your necromancy spells, you may force that creature to reroll the saving throw. The creature must use the second result.

As an action on each of your turns, you may command the throne to perform one of the following functions:

Soul Furnace

Soul-fire erupts from vents and chimneys across the throne.

Each hostile creature of your choice within 30 feet of the throne must make a Constitution saving throw. A creature takes 8d10 necrotic damage on a failed save, or half as much damage on a successful one.

Bone Foundry

The throne disgorges skeletal warriors forged from compressed bone and soul ash.

You summon six Bone Legionnaires in unoccupied spaces within 30 feet of the throne. The legionnaires use the Skeleton stat block with the following changes:

• Their hit points become 30.

• Their attacks deal an additional 1d6 necrotic damage.

• They act immediately after your turn.

The legionnaires remain until destroyed or until the spell ends.

Engine Pulse

The Black Engine releases a thunderous shockwave of grinding gears, screaming spirits, and unstable chaos energy.

Each hostile creature within 60 feet of the throne must succeed on a Strength saving throw or take 4d10 force damage, be pushed up to 20 feet away from the throne, and fall prone. On a successful save, the creature takes half damage and suffers no additional effects.

When the spell ends, the throne collapses into ash, bone fragments, and unstable Grind residue.

Rumors persist that the Black Engine beneath the Bone Caravan is not merely inspired by this spell.

Some believe the spell is a miniature version of the Engine itself.

Others suspect something far worse.

They believe the Horned King did not invent Throne of the Black Engine.

They believe he discovered it.

And if that is true, then somewhere in the wastelands there may be a larger throne waiting for its rightful ruler.

Bringing These Spells Into Your Campaign

Neither of these spells should be treated as ordinary treasure.

They are campaign-defining discoveries.

A Grind Baron might murder entire districts to obtain one. A cult could worship fragments of the research that created them. An entire adventure could revolve around preventing a rival necromancer from reconstructing even part of the Horned King’s notes.

Most frightening of all, neither spell is inherently evil.

Both were designed to solve problems.

To preserve soldiers.

To strengthen settlements.

To help civilization survive.

Like the Bone Caravan itself, their horror lies not in what they do.

But in how reasonable they begin to sound after the apocalypse has lasted long enough.

Thanks for reading. Until Next time, Stay Nerdy!!