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Under the Dome: The Horned King’s Arsenal

The King Who Became a Kingdom

Most rulers possess power.

The Horned King became power.

For centuries, the master of the Bone Caravan has crossed the wastelands beneath his mobile Dome of bone and death. Entire cities fear his arrival. Raiders vanish before his armies. Chaos storms bend around his fortress. Even the Grind Barons, who measure everything in profit and leverage, speak carefully when discussing the ruler beneath the Bone Caravan.

Yet despite all the stories told about him, one truth remains constant:

The Horned King rarely leaves his throne.

Not because he cannot.

Because he rarely needs to.

When he finally rises to take the field himself, something has gone catastrophically wrong.

Or exactly according to his plan.

Today we explore the Horned King as a legendary foe suitable for high-level campaigns, along with the artifact that helped transform him from a conquering minotaur into the immortal sovereign of the dead.

The Bonecleaver of Endless Dominion

Every king requires a symbol of authority.

The Horned King’s symbol happens to be capable of splitting a fortress wall in half.

Known as the Bonecleaver of Endless Dominion, this artifact appears as an immense greataxe forged from black iron, storm-glass, and polished bone. Veins of pale green energy pulse beneath its surface like blood moving through living flesh.

Yet the weapon is more than an axe.

At the center of its haft rests a crystalline core harvested from the heart of an ancient chaos storm. Necromantic runes spiral around the shaft, allowing the Bonecleaver to function as both a devastating melee weapon and an unparalleled arcane focus.

Many scholars believe the weapon predates the Bone Caravan itself.

Others believe the weapon helped create it.

The Horned King has never clarified the truth.

Bonecleaver of Endless Dominion

Artifact (requires attunement by a spellcaster, martial character, or creature with Strength 15 or higher)

The Bonecleaver functions as a +3 Greataxe and a +3 Arcane Focus.

While attuned to the weapon, you gain the following benefits:

• Your Strength or spellcasting ability increases by 2, to a maximum of 24.
• You gain resistance to necrotic damage.
• You may use Strength for spell attack rolls and spell save DCs if desired.
• You learn the finger of death spell and may cast it once per long rest without expending a spell slot.

Reaper’s Harvest

Whenever you reduce a creature to 0 hit points, gain temporary hit points equal to your proficiency bonus plus your spellcasting modifier.

Lord of the Fallen

As an action, once per day, you may animate up to six corpses within 60 feet as undead under your control for 1 hour.

Chaos Dominion

Once per long rest, you may unleash a wave of destructive energy in a 60-foot cone.

Creatures in the area must make a DC 22 Constitution saving throw.

On a failure they take 12d10 necrotic damage and 12d10 force damage.

On a success they take half damage.

The terrain in the cone becomes difficult terrain until the next dawn.

Curse of the Bone King

The weapon seeks rulers.

A creature unattuned to the philosophy of domination and control gradually develops obsessive desires to impose order on others.

The longer the artifact is wielded, the harder these impulses become to resist.

The Horned King

Gargantuan Undead, Lawful Evil

Armor Class 24 (Necrotic Plate)

Hit Points 750

Speed 40 ft.

STR 30 (+10)
DEX 14 (+2)
CON 30 (+10)
INT 22 (+6)
WIS 22 (+6)
CHA 26 (+8)

Saving Throws Str +18, Con +18, Wis +14, Cha +16

Damage Resistances Cold, Fire, Lightning

Damage Immunities Necrotic, Poison

Condition Immunities Charmed, Exhaustion, Frightened, Paralyzed, Poisoned

Senses Truesight 120 ft.

Languages All, Telepathy 300 ft.

Challenge Rating 30

Living Fortress

The Horned King cannot be forcibly moved, knocked prone, or restrained.

Master of Death

Undead creatures within 120 feet gain advantage on saving throws and deal an additional 10 necrotic damage on weapon attacks.

Lord of the Bone Caravan

If fought within the Bone Caravan, the Horned King regains 30 hit points at the start of each turn.

Legendary Resistance (5/Day)

If the Horned King fails a saving throw, he can choose to succeed instead.

Actions

Multiattack

The Horned King makes three Bonecleaver attacks and casts one spell.

Bonecleaver

Melee Weapon Attack: +18 to hit.

Hit: 4d12 + 10 slashing plus 4d10 necrotic damage.

Cataclysmic Sweep (Recharge 5-6)

The Horned King swings Bonecleaver in a massive arc.

All creatures within 30 feet must make a DC 26 Dexterity saving throw.

Failure: 12d10 slashing plus 12d10 necrotic damage and knocked prone.

Success: Half damage.

Spellcasting

The Horned King is a 20th-level spellcaster.

Spell Save DC 24

At Will:
blight, counterspell, dispel magic

3/day:
finger of death, circle of death, wall of force

1/day:
power word kill, meteor swarm

Bonus Actions

Command the Dead

One undead creature may immediately take an action.

Soul Harvest

Choose a creature that died within the last round.

The Horned King regains 25 hit points.

Legendary Actions

The Horned King can take 3 legendary actions.

Bone Step

Teleport up to 60 feet.

Grave Bolt

A creature within 120 feet takes 4d10 necrotic damage.

Unleash Legion (Costs 2 Actions)

Summon 2d4 Bone Legionnaires.

Reality Scar (Costs 3 Actions)

Open a tear in reality.

Creatures in a 20-foot radius must succeed on a DC 24 Constitution save or take 8d10 force damage and become frightened.

Mythic Phase: The King and the Kingdom Are One

When reduced to 0 hit points, the Horned King does not die.

Instead, his body fractures apart into swirling bone fragments and storm-lit necrotic energy.

He immediately regains 400 hit points.

The Bone Caravan awakens.

For the remainder of the encounter:

• Initiative count 20 triggers a lair action every round.
• Massive skeletal limbs erupt from walls and floors.
• The battlefield continuously reshapes itself.
• Undead gain advantage on all attacks.
• The Horned King’s attacks deal an additional 3d10 force damage.

Only after this second form is defeated can he truly be destroyed.

And even then, no one is entirely certain.

Using the Horned King in Your Campaign

The Horned King should never simply be a monster waiting in a dungeon.

He is a campaign.

His armies should be encountered long before he appears. His philosophy should challenge players before his weapons do. Entire adventures should revolve around deciding whether his vision of survival is monstrous, practical, or both.

When the players finally stand before him, the battle should feel less like fighting a lich and more like confronting a civilization that has chosen immortality over humanity.

Because the Horned King is not merely an undead ruler.

He is proof that the apocalypse created new kinds of monsters.

And some of them learned how to build kingdoms.

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