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Dagon, Demon Lord Prince of the Sea

Large fiend (demon lord), chaotic evil

Armor Class 19 (natural armor)
Hit Points 472 (35d10 + 280)
Speed 20 ft., swim 60 ft.

25 (+7) 18 (+4) 27 (+8) 18 (+4) 20 (+5) 19 (+4)

Saving Throws Dexterity +12, Constitution +16, Wisdom +13, Charisma +12
Skills Athletics +15, History +12, Insight +13, Intimidation +12, Perception +13
Damage Resistances cold, fire, lightning
Damage Immunities poison; bludgeoning, piercing, and slashing from nonmagical weapons
Condition Immunities charmed, exhaustion, frightened, poisoned
Senses truesight 120 ft., passive Perception 23
Languages Abyssal, Celestial, Common, Draconic, Giant, Infernal; telepathy 120 ft.
Challenge 26 (90,000 XP)

Special Traits


  • Multiattack. Dagon makes three melee weapon attacks.
  • Embrace of the Uncaring Sea. Melee or Ranged Weapon Attack: +18 to hit, reach 10 ft. or range 20/60 ft., one creature. Hit: 24 (4d6 + 10) piercing damage, or 28 (4d8 + 10) piercing damage if used with two hands to make a melee attack, plus 17 (5d6) poison damage. If Dagon rolls a natural 19 or 20, the target must make a DC 21 Constitution saving throw or be afflicted by the crushing pressure of the sea. A creature afflicted by this cannot breathe, use verbal components, or take actions or reactions. At the end of each of the target’s turns, it can repeat the saving throw, ending the effect on a success. Magic such as heal can end this affliction early.
  • Claw. Melee Weapon Attack: +15 to hit, reach 5 ft., one target. Hit: 25 (4d8 + 7) slashing damage and target is poisoned until the beginning of Dagon’s next turn.
  • Command Aquatic Creature (Recharge 5–6). One creature with a swim speed that Dagon can see within 120 feet of it hears the telepathic commands of Dagon and must make a DC 21 Wisdom saving throw. On a failed save, the creature is charmed for 24 hours. While charmed, it must follow the orders of Dagon to the best of the target’s ability and it is immune to being charmed or frightened by another effect or spell. A target can repeat the saving throw when it takes damage, ending the effect on a success.

Legendary Actions

Dagon 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. Dagon regains spent legendary actions at the start of its turn.

  • Move. If at least halfway submerged in water, Dagon can move up to half its swim speed without provoking opportunity attacks.
  • Command Aquatic Creature (Costs 2 Actions). Dagon uses its Command Aquatic Creature ability, even if it has not recharged.
  • Ink Cloud (Costs 3 Actions). Dagon exhales a 60-foot cone of inky blackness. Underwater it is as black ink, while above water it manifests as a thick cloud, and the area counts as heavily obscured. It remains until dispersed by a strong current or wind (at least 20 miles per hour). Dagon can end this effect on its turn as a bonus action. Creatures who enter or begin their turn in the area must make a successful DC 22 Constitution saving throw or take 18 (4d8) poison damage.

Lair Actions

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

  • Maelstrom. The currents and eddies of the underwater realm Dagon occupies swirl in a maelstrom out to a radius of 100 feet. All creatures in that area, other than Dagon, must make a DC 21 Strength saving throw. On a failed save, the target is moved in a random direction 30 feet.
  • Control Temperature. Dagon selects an area of water within 100 feet no larger than a 20-foot sphere and causes it to heat to boiling or cool drastically. Any creature within that area must make a DC 21 Constitution saving throw, taking 27 (6d8) cold or fire damage on a failed save, or half as much on a successful saving throw.

Regional Effects

The region containing Dagon’s lair is warped by its magic, creating one or more of the following effects: Aquatic Bestiary. Aquatic creatures of all types are drawn to Dagon’s presence; often they are only hostile to non-aquatic creatures.

Unusual Weather. Once per day, Dagon can control the weather surrounding his lair out to a 6-mile radius. The effect is identical to the control weather spell.

Adverse Conditions. Within 1 mile of the lair, Celestial creatures find the air or water difficult to breathe and tread. These creatures must make a DC 18 Constitution saving throw whenever they take a long rest. On a failed save, the creature does not benefit from that long rest.

If Dagon is slain, changed weather reverts to normal as described in the spell, and the other effects fade in 1d10 days.


This creature has the upper body, arms, and head of a green-skinned humanoid, and the lower torso of a great scaled fish. A thin, almost translucent fin runs the length of his back, and a long mane of black hair falls from his head and down his finned back. His eyes are crimson.

Dagon is the demon prince of sea creatures. He is worshipped as a deity by legions of sahuagin, locathah, skum, lizardfolk, tritons (those that have accepted the ways of evil), and some merfolk. His Abyssal lair is not unlike the Elemental Plane of Water in that it is composed entirely of water. Pockets of air, though, are rumored to be trapped in invisible “bubbles” throughout his lair (so as to allow the non-water breathing demons to exist comfortably). Dagon makes his home in a great underwater iron citadel called Thos located in the deepest recesses of his home plane.

Dagon appears as a 10-foot-tall merman and weighs about 2,000 pounds. He can move on land using his fists to drag or pull his body but prefers to remain in water whenever possible.

Dagon prefers to use his trident in battle but can attack with his powerful fists if he so chooses.

Servants of Dagon

Followers of Dagon are mermen, locathah, sahuagin, lizardfolk, skum, and evil humanoids that revere the seas and oceans. Devout followers of Dagon are called Scaled Ones and must sign a pact of evil with Dagon.

Section 15: Copyright Notice

Tome of Horrors © 2018, Frog God Games, LLC; Authors: Kevin Baase, Erica Balsley, John “Pexx” Barnhouse, Christopher Bishop, Casey Christofferson, Jim Collura, Andrea Costantini, Jayson ‘Rocky’ Gardner, Zach Glazar, Meghan Greene, Scott Greene, Lance Hawvermale, Travis Hawvermale, Ian S. Johnston, Bill Kenower, Patrick Lawinger, Rhiannon Louve, Ian McGarty, Edwin Nagy, James Patterson, Nathan Paul, Patrick N. Pilgrim, Clark Peterson, Anthony Pryor, Greg Ragland, Robert Schwalb, G. Scott Swift, Greg A. Vaughan, and Bill Webb