Linnorm, Midgard Serpent

Family: Linnorm

Gargantuan dragon (titan), unaligned

Armor Class 19 (natural armor)
Hit Points 553 (27d20+270)
Speed swim 100 ft.

30 (+10) 16 (+3) 30 (+10) 3 (-2) 24 (+7) 29 (+9)

Saving Throws Cha +18, Con +19, Str +19
Damage Resistances lightning, fire, necrotic, thunder; bludgeoning, piercing, and slashing from nonmagical attacks
Damage Immunities acid, cold
Condition Immunities charmed, frightened, paralyzed
Skills Athletics +19, Perception +16
Senses darkvision 120 ft., passive Perception 26
Languages Aquan, Giant (can’t speak)
Challenge 30 (155,000 XP)

Special Traits

  • Innate Spellcasting. The Midgard Serpent’s spellcasting ability is Charisma (spell save DC 26). It can innately cast the following spells, requiring no material components:
  • Legendary Resistance (3/Day). If the Midgard Serpent fails a saving throw, it can choose to succeed instead.
  • Massive Size. The Midgard Serpent occupies a space of 60 feet by 60 feet instead of the space a Gargantuan creature would normally occupy.
  • Siege Monster. The Midgard Serpent deals double damage to objects and structures.
  • Solid Fog. Whenever the Midgard Serpent casts fog cloud, the area that the spell occupies is also considered difficult terrain. All melee weapon attack rolls within this area are made with disadvantage, except for the Midgard Serpent’s attacks. Ranged weapon attacks simply fail within this area, as the fog is far too thick to have projectiles make it through.
  • Water Breathing. The Midgard Serpent can only breathe underwater.


  • Multiattack. The Midgard Serpent makes one bite attack and one tail attack.
  • Bite. Melee Weapon Attack: +14 to hit, 60 ft. reach, one target. Hit: 75 (10d12 + 10) bludgeoning damage plus 65 (10d12) poison damage.
  • Tail. Melee Weapon Attack: +14 to hit, 60 ft. reach, all targets within reach. Hit: 43 (6d10 + 10) piercing damage. The Midgard Serpent can choose to grapple one creature it hits instead of dealing damage (escape DC 23).

Legendary Actions

The Midgard Serpent can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The Midgard Serpent regains spent legendary actions at the start of its turn.

  • Charming Gaze (Costs 2 Actions). The Midgard Serpent can focus its gaze on one creature which must succeed a DC 23 Wisdom saving throw or become charmed by the Midgard Serpent. A charmed creature can attempt a saving throw at the end of each of its turns to end the condition.
  • God-Eater. The Midgard Serpent learns the location of all celestials and fiends as well as clerics and paladins who gain their power from a deity within 60 feet of it. It may immediately make a bite attack against one such creature if there is one within range.
  • Unnerving Aura. All creatures within 60 feet of the Midgard Serpent must succeed a DC 23 Wisdom saving throw or become frightened of the Midgard Serpent. A frightened creature can attempt a saving throw at the end of each of its turns to end the condition.


On initiative count 20 (losing initiative ties), the Midgard Serpent takes a lair action to cause one of the following effects; The Midgard Serpent can’t use the same effect two rounds in a row:

  • A Midgard Serpent can summon one creature that swims and breathes water of CR 2 or less to a space within 60 feet of it. This creature is loyal to the Midgard Serpent and will do anything to defend it.
  • The Midgard Serpent can cause a 10-foot-radius square of water within 60 feet to superheat. Any creatures in those squares must succeed a DC 23 Constitution saving throw or take 7 (2d6) fire damage.
  • The Midgard Serpent can cause a 10-foot-radius whirlpool to form in a space within 60 feet of it. All creatures within this area must succeed a DC 23 Dexterity saving throw or be restrained for 1 round.

Regional Effects

The region containing the Midgard Serpent’s lair is shaped by its titanic power, which creates one or more of the following effects:

  • Underwater lightning storms become frequent, with electricity occasionally arcing through the sea floor and hotspots of boiling water becoming commonplace
  • Religious symbols become hot to the touch, almost becoming unbearable to wield within 1 mile of the Midgard Serpent’s lair.
  • The lighting within 1 mile of the Midgard Serpent’s lair becomes dim lighting that is impossible to brighten. The area within 150 feet of the Midgard Serpent’s lair is darkness that is impossible to brighten.


The Midgard Serpent is the greatest of linnorms, the unbounded spawn of a treacherous godling and his monstrous bride. Cast into the sea by the when it and its monstrous siblings were discovered, this beast is fated to one day devour the mightiest of the gods. The Midgard Serpent’s appetite is endless, as it gorges itself for weeks at a time before descending into the deepest depths of the ocean to drift in the inky depths for years or decades at a time before rising once more to feast. Also called Jormungandr, the Midgard Serpent is over 500 feet long and weighs over 20,000 tons.

Legendary Destroyer. The Midgard Serpent is a solitary beast, tolerating no rivals in the deep waters where it swims. It preys upon ordinary aquatic animals like whales and squid, but also happily devours dragon turtles, krakens, and lesser linnorms, and can depopulate entire cities of aquatic races like sahuagin and merfolk. When it roams close to the surface, storms follow in its wake, and ships are shattered with ease beneath its coils as their crews are devoured. On rare occasions it ventures near to shore, usually when pursuing a ship fleeing before it, and may devastate coastal communities with its onslaught as the storm-tossed sea rises up around it, but it soon retreats to the deep oceans it favors.

God-Eater. The Midgard Serpent is a unique creature, though kin to other great monsters like Fenris Wolf sired by the same forbidden liaisons that gave birth to it. Cast into the sea by the gods long ago, the Midgard Serpent still holds great enmity toward them and their servants, and seeks out divine servants to devour with especial relish. If he chances upon shrines to the gods, he always takes the time to demolish, despoil, and pollute them, vomiting forth his vile and corrupted poisons into the ruins left behind. Jormungandr is not particular in his hatred of the gods, and is equally happy to destroy spaces both sacred and profane. He is a devourer of both magic as well as flesh, consuming the latent magical energies of the world and drawing in the life-giving essence of the universe with every breath. His presence disrupts natural weather and brings with it disastrous storms and a dimming of the light of the world.

He is a creature of pure hate, looking always towards that faroff day when the world draws down to its bitter, frozen ending and he and the other great beasts of the world rise up and devour the gods who once cast them down.

Section 15: Copyright Notice

Sea Monsters (5E) © 2021, Legendary Games; Authors Michael Ritter, Michael “solomani” Mifsud, Robert J. Grady, Mark Hart, Jeff Ibach, Alex Riggs, Scott D. Young, Jeff Lee, Matt Kimmel, and Jason Nelson.

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