Dagon

Huge aberration, chaotic evil

Armor Class 24 (natural armor)
Hit Points 406 (28d12+224)
Speed 40 ft., swim 120 ft.

STR	DEX	CON	INT	WIS	CHA
26 (+8)	21 (+5)	26 (+8)	25 (+7)	26 (+8)	25 (+7)

Skills Arcana +15, Athletics +16, Deception +15, History +15, Insight +16, Intimidation +15, Investigation +15, Nature +15, Perception +16, Religion +15, Stealth +13
Damage Resistances acid, fire, necrotic; bludgeoning, piercing, and slashing
Damage Immunities cold, lightning; bludgeoning, piercing, and slashing from nonmagical attacks not made from cold iron
Condition Immunities charmed, diseased, frightened, paralyzed, petrified
Senses truesight 120 ft., passive Perception 26
Languages Abyssal, Aquan, Celestial, Common, Deep Speech, Draconic; telepathy 300 ft.
Challenge 28 (120,000 XP)

SPECIAL TRAITS

• Command Sea Creatures. Once per turn, Dagon can command aquatic creatures to do its bidding. This affects all aberrations, beasts, and oozes within 300 feet that are able to breathe water (a DC 24 Wisdom saving throw negates). This functions like mass suggestion, but can affect mindless creatures. Dagon can suggest obviously harmful or suicidal acts (though non-mindless creatures have advantage and a +5 bonus on their saving throws against these suggestions). The commanded course of activity can have a duration of up to 1 hour. If Dagon issues a new command to a creature, the previous command is discarded. A creature that successfully resists this effect is immune to further commands from Dagon for 24 hours.
• Immortality. When Dagon is reduced to 0 hit points, its body liquifies and emits a noxious otherworldly cloud in a 15-foot radius. Any creature that comes into contact with the amorphous puddle makes a DC 24 Wisdom saving throw or takes 54 (12d8) necrotic damage and 54 (12d8) poison damage. Each round, Dagon’s puddle moves 50 feet towards the nearest large body of water (lake or bigger), ignoring difficult terrain. If it reaches a large body of water within 10 minutes, it takes 2d6 minutes before Dagon is restored to life via resurrection. It comes back to life with 5 levels of exhaustion and cannot take both a move and action in the same turn. At the end of each minute, Dagon makes a DC 20 Constitution saving throw to reduce its exhaustion level by 1. If slain again while suffering from this effect, Dagon reverts to liquid form again and if it does not reach a large body of water within 1 minute its essence fades (and should it reach the water, it takes 2d6 hours before it is returned to life).
• Innate Spellcasting. Dagon’s innate spellcasting ability is Wisdom (spell save DC 24; spell attack +16). It can innately cast the following spells, requiring no material components:
  • Constant: detect evil and good, freedom of movement, speak with animals (aquatic only), true seeing
  • At will: astral projection, control water, control weather (no concentration), detect thoughts, dispel magic, hallow (evil only), polymorph, symbol, telekinesis, teleport
  • 1/day: time stop
• Insanity. Any creature that attempts to interact directly with Dagon’s thoughts (such as via detect thoughts or telepathy) must succeed at DC 24 Wisdom saving throw or gain an indefinite madness. When using its telepathy to communicate Dagon doesn’t activate this feature unless it spends a bonus action to focus its mind on one opponent.
• Legendary Resistance (3/Day). If Dagon fails a saving throw, it can choose to succeed instead.
• Magic Resistance. Dagon has advantage on saving throws against spells and other magical effects.
• Regeneration. Dagon regains 20 hit points at the start of its turn if it has at least 1 hit point.

ACTIONS

• Multiattack. Dagon can use its Frightful Presence. It then twice with its bite and twice with its claws.
• Bite. Melee Weapon Attack: +16 to hit, reach 15 ft., one target. Hit: 24 (3d10+8) piercing damage. Instead of dealing damage, Dagon can Swallow the target.
• Claws. Melee Weapon Attack: +16 to hit, reach 25 ft., one target. Hit: 21 (3d8+8) slashing damage. If the target is a creature, it is grappled (escape DC 24). Until the grapple ends, the target is restrained.
• Frightful Presence. Each creature of Dagon’s choice that is within 120 feet of Dagon and aware of it must succeed on a DC 24 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to Dagon’s Frightful Presence for the next 24 hours.
• Poisonous Miasma (Recharge 4-6). Dagon exhales inky blackness in a 60-foot cone (ink if underwater or a cloud otherwise). Creatures in the area are blinded unless they have truesight. The ink or smoke remains for 1d4 rounds, or only 1 round if in an area of high current or winds. Each creature in the area or entering the area must make a DC 24 Wisdom saving throw, taking 54 (12d8) necrotic damage and 54 (12d8) poison damage on a failed save, or half as much damage on a successful one.
• Swallow. Dagon makes one bite attack against a Medium or smaller creature it is grappling. If the attack hits, that creature takes the bite’s damage and is swallowed, and the grapple ends. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside Dagon. At the start of each of Dagon’s turns the swallowed creature takes 21 (6d6) necrotic damage, 21 (6d6) poison damage, and it makes a DC 24 Wisdom saving throw. Once the swallowed creature has failed its save three times, it is transformed into a deformed parody of itself that Dagon can use a bonus action to disgorge into an adjacent square. The transformed creature has advantage on attack rolls, a +5 bonus to AC, and is under Dagon’s control (as dominate monster but without the need for concentration). The transformation can be reversed by casting heal or regenerate within the first 24 hours. If Dagon takes 30 damage or more on a single turn from a creature inside it, Dagon must succeed on a DC 15 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of Dagon. If Dagon dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 15 feet of movement, exiting prone.

ABOUT

Numerous terrors prowl the depths of the ocean and the fiercest of them all is one feared equally by those beneath and those above: Dagon.

Thought by some to be an Elder God that has existed since before all other deific pantheons, it is nightmare given form and a timeless horror from below the waves, undisputed master of the realms aquatic-though how and where it exerts influence cannot be fathomed by mortal minds.

Countless cults devoted to appeasing or summoning this ancient horror have come, gone, and spawn anew as time passes, only a rare few managing to garner Dagon’s attention for very long. Even then it doesn’t matter much; when it deigns to visit the Material Plane the entity undertakes region-spanning rituals by, scouring the seabeds with furrowed runes dozens of miles across, and any favor it grants is the merest expression of its power. More troublesome are the insane pirates that show fealty to the Elder God, sacrificing whole ships and every soul aboard to gain its favor or blessing.

Dagon values this devotion and welcomes those who prove their worth by reaching it so long as they pay it proper respect with a gift commensurate to its greatness-a powerful magic item of rare or greater rarity appeases it, as does a living sacrifice of a creature that’s CR 9 or greater, or the trapped soul of sufficient worth. The first task the ancient horror puts upon new servants is to go out and acquire more followers and gifts for it. Only after proving themselves enough times are given more important missions (like acquiring someone with a potent bloodline, tracking down an artifact, or interfering with the doings of other Elder Gods). A creature that angers Dagon is almost certainly doomed and can rarely hide for long, the creatures of the sea are constantly searching for their master’s enemies. When the foe is found the ancient horror imparts madness upon its enemy, then engages directly by spreading poison all about before it rends them apart. Anything still alive after its fury is sated is captured and then driven utterly insane, tormented for days or even weeks before their soul is consumed. Whenever mortals interact with Dagon, the GM should emphasize the Elder God’s extreme power and not undersell the danger it poses-even if they do manage to trick it, any ruse is only going to last for so long before it invites terrible retribution.