Robert

Frozen King Boss Fight

The Crown of the Forge is a tall dormant volcano, and it is easily seen all throughout the Forge Lands. The peak of this mountain is high and always covered in a thick layer of snow year-round. Sages don’t know why this is the case, since the Forge Lands’ climate is fairly warm and other peaks may not even have any snow during the winter. The Dwarves know better, however, for up on the mountain dwells an old elemental spirit who keeps the mountain frozen. The Dwarves know because their ancient ancestors put it there, to keep the old volcano cool and dormant.

Phased Boss Monster

The Frozen King is a Phased Boss monster and uses the rules from our Phased Boss Fight article we posted last month (Do You Want to Know More?). The reason why the players will need to battle this old elemental monster is up to you. Perhaps it has gone mad, and the perpetual winter it brings is now spreading out from the tallest mountain. Perhaps somebody has pulled it from the mountain and the Frozen King has started ravaging the nation. Or perhaps the players stumble upon it while exploring frosty caves in the Underdark.

Phase 1
When first encountered, the Frozen King is oddly hard to see for such a huge creature. The very air around it is a frozen snowy mist. The players will more likely first feel the shaking from its heavy footsteps, and hear the cracking grinding of his movements that sound like a glacier.

Skill Checks

Intelligence (Arcane) DC 20 – the Frozen King is a powerful unique elemental

Intelligence (History) DC 20 – the Frozen King of the Mountain is a elemental that lives on a tall mountain. It is said to bring winter to that mountain peak year- round.

Frozen King of the Mountain
Huge elemental, neutral
Armor Class 18 (natural armor)
Hit Points 187 (15d12 + 90)
Speed 30ft., burrow 30ft
Str 22 (+6), Dex 8 (-1), Con 23 (+6), Int 6 (-2), Wis 10 (+0), Cha 8 (-1)
Damage Vulnerabilities fire
Damage Resistances bludgeoning, piercing, and slashing from nonmagical weapons
Damage Immunities cold, poison
Condition Immunities exhaustion, paralyzed, petrified, poisoned, unconscious
Senses darkvision 120ft, tremor sense 120 feet., passive perception 10
Languages Aquan, Auran, Ignan, Terran
Challenge 14 (11,500)

Frozen Earth Glide. The Frozen King can burrow through nonmagical unworked earth and stone, as well as ice and snow. While doing so, the Frozen King doesn’t disturb the material it moves through.
Frozen Ground. The ground around the Frozen King freezes over in a layer of ice, making it easy for creatures to lose their balance. At the end of their turn, any creature standing within 10 feet of the Frozen King must make a Dexterity save (DC 15) or fall Prone.
Siege Monster. The Frozen King deals double damage to objects and structures.
Snowfall. The Frozen King generates a cloud of frozen mist and snow around it, because of this it is always has the benefits of half cover for ranged attacks.

Actions
Multiattack. The Frozen King makes two slam attacks.
Slam. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) bludgeoning damage plus 10 (3d6) cold damage.

Legendary Actions
The Frozen King of the Mountain can take 3 legendary actions, using the Frost Spike option below. It can take only one legendary action at a time and only at the end of another creatures turn. The Frozen King of the Mountain regains spent legendary actions at the start of its turn.
Frost Spike. The Frozen King makes a spike of ice erupt from the ground within 100 feet of it. The targeted creature must succeed on a DC 15 Dexterity saving throw or take 10 (3d6) cold damage on a failed save, or half as much damage on a successful one.

Phase 2
As your party attacks the Frozen King of the Mountain, they slowly chip the ice off his exterior, revealing the cold rocky core of the beast. When Phase 1 Frozen King reaches 0 Hit Points, it transitions to Phase two and any remaining ice left on it falls to the ground and the cloud of cold mist around it evaporates. At this point, it looks mostly like a Huge Earth Elemental, but there is a cold light emanating through the cracks in the rocks it is made of. The Frozen King becomes enraged, focusing on whatever dealt it the most damage on it in the last turn, and it will move toward whatever damaged it most, not caring about attacks of opportunity.

King of the Mountain
Huge elemental, neutral
Armor Class 19 (natural armor)
Hit Points 187 (15d12 + 90)
Speed 30ft., burrow 30ft
Str 22 (+6), Dex 10 (-0), Con 23 (+6), Int 6 (-2), Wis 10 (+0), Cha 8 (-1)
Damage Resistances bludgeoning, piercing, and slashing from nonmagical weapons
Damage Immunities cold, poison
Condition Immunities exhaustion, paralyzed, petrified, poisoned, unconscious
Senses darkvision 120ft, tremor sense 120 feet., passive perception 10
Languages Aquan, Auran, Ignan, Terran
Challenge 14 (11,500)

Earth Glide. The King of the Mountain can burrow through nonmagical unworked earth and stone. While doing so, the Frozen King doesn’t disturb the material it moves through.
Enraged. The King of the Mountain has advantage on all melee weapon attack rolls during its turn, but attack rolls against it have advantage.
Siege Monster. The King of the Mountain deals double damage to objects and structures.

Actions
Multiattack. The King of the Mountain makes two slam attacks.
Slam. Melee Weapon Attack: +10 to hit, reach 10 ft., one target Hit: 28 (4d10 + 6) bludgeoning damage.

Legendary Actions
The King of the Mountain can take 3 legendary actions, using the Slam or Teleport option below. It can take only one legendary action at a time and only at the end of another creatures turn. The King of the Mountain regains spent legendary actions at the start of its turn.
Teleport. The King of the Mountain magically teleports, up to 60 feet to an unoccupied space it can perceive. When it does this the elemental literally falls apart in a flash of cold light and rebuilds itself.
Slam. The King of the Mountain makes a slam attack to a creature within range.

Phase 3
As the party continues hacking away at the elemental, chunks of rock splinter off of it, adding more clutter to the ground. What lies beneath is a cold shimmering radiance of the King of the Mountain’s true form, the Frost Elemental Core. Once the King of the Mountain gets to zero hits points, the remaining stone cracks and splinters off the body, revealing the true form of the creature. At this point the rage in the creature cools off, and it attacks in a much more cold and intelligent way.

Frost Elemental Core
Huge elemental, neutral
Armor Class 15
Hit Points 127 (15d12 + 30)
Speed 0 ft., fly 90 ft. (Hover)
Str 14 (+2), Dex 20 (+5), Con 15 (+2), Int 6 (-2), Wis 10 (+0) Cha 8 (-1)
Damage Vulnerabilities Fire
Damage Resistances bludgeoning, piercing, and slashing from nonmagical weapons
Damage Immunities cold, poison
Senses darkvision 120ft, tremor sense 120 feet., passive perception 10
Languages Aquan, Auran, Ignan, Terran
Challenge 11 (10,000)

Snow Form. The Frost Elemental can move through a space as narrow as 1 inch wide without squeezing. A creature that touches the Frost Elemental or hits it with a melee attack while within 5 feet takes 7 (2d6) cold damage. In addition, the elemental can enter a hostile creature’s space and stop there. The first time it enters a creature’s space on a turn, that creature takes 7 (2d6) cold damage.

Actions
Multiattack. The Frost Elemental makes two slam attacks.
Slam. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit 19 (4d6 + 5) cold damage.
Ice Blast (Recharge 5-6). The Frost Elemental emits a wind that flash freezes enemies in a 60 foot line that is 10 feet wide. Each creature in that line must make a DC 17 Dexterity saving throw, taking 14 (4d6) cold damage, or half as much on a successful saving throw. Furthermore each creature must make a DC 15 Constitution saving throw or become restrained as the cold settles into their bones.

Legendary Actions
The Frost Elemental Core can take 3 legendary actions, using the Cone of Cold, Frost Cage, or Ray of Frost option below. It can take only one legendary action at a time and only at the end of another creatures turn. The King of the Mountain regains spent legendary actions at the start of its turn.
Cone of Cold (Costs 3 Legendary Actions). The Frost Elemental Core casts the spell Cone of Cold. 36 (8d8) Damage, DC 17 Constitution Saving Throw.
Frost Cage. The Frost Elemental Core raises a icy mist that flash freezes over a target. The target must make a DC 17 Dexterity save or become restrained.
Ray of Frost. the Frost Elemental Core casts ray of frost as a 11th level spell caster. +9 Spell attack, 13 (3d8) damage.

Victory
When the party defeats the Frozen King of the Mountain they divide 33,000 experience between them, plus any adjustments for Multipart Encounters (Dungeon Masters Guide pg 82). Since it is a unique elemental being, you can allow the option for players to craft magic items from the remains. For example, you can use its icy heart to craft a Staff of Frost, or craft a shard of its stone skin into a club or mace that deals extra cold damage. With a DC 15 Intelligence (Arcana) check, players will know that once dead, the Frozen King of the Mountain’s spirit will return to its home plane and will, in time, re-form. Therefore the only way to truly kill it is to defeat it on its home plane. You can choose its home plane to be one of the elemental planes, or you can choose to make that the Mountain it was bound to.

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