Deep One Hybrid Cultist

Family: Deep One

Medium humanoid (human, mythos), chaotic evil

Armor Class 12 (natural armor)
Hit Points 13 (2d8+4)
Speed 20 ft., swim 30 ft.

11 (+0) 12 (+1) 12 (+1) 10 (+0) 12 (+1) 10 (+0)

Skills Deception +2, Religion +2
Senses darkvision 60 ft., passive Perception 11
Languages Deep Speech, Common
Challenge 1/8 (25 XP)

Special Traits

  • Dark Devotion. A deep one hybrid cultist has advantage on saving throws against being charmed or frightened.
  • Final Change. A deep one hybrid ages faster than a human. A mere 1d12 months after a deep one hybrid reaches venerable age at 60 years old, it dies a painful, agonizing death, only to have its body transform into that of a mature deep one. This transformation functions as the reincarnate spell.
  • Hold Breath. The deep one hybrid can hold its breath for 15 minutes.
  • Sea Longing. Every 24 hours a deep one hybrid spends more than 10 miles from the sea, it must succeed on a DC 15 Wisdom saving throw. On a failure, the deep one hybrid has disadvantage on ability checks, attack rolls, and saving throw. If the deep one hybrid is already suffering this penalty, it takes 1d6 psychic damage on a failure. The deep one hybrid no longer suffers this disadvantage once it has spent 24 hours within 10 miles of the sea.


  • Scimitar. Melee Weapon Attack: +3 to hit, 5 ft. reach. Hit: 4 (1d6 + 1) slashing damage.


Deep ones are as at ease dwelling in the most remote of ocean trenches as they are in the shallows that hug secluded shorelines, although their favorite haunts combine the two.

The largest deep one cities are located at places not far off shore but nestled in vast submerged canyons unusually close to those coastlines. This proximity allows deep ones to pursue one of their favorite goals-commingling with and corrupting surface-dwelling humanoids. Deep ones do so not out of a biological need but as a way to spread their blasphemous religion above the ocean waves. The hybrid children of deep ones and humans form a race of their own. These offspring typically live near others of their kind, assuming positions of leadership in their small towns. A deep one’s gray-green hide glistens with moisture, and saliva dribbles from its fishlike maw.

Deep Devotees. Deep ones usually worship the alien entities known as the Outer Gods or the Great Old Ones, with cthulhu the foremost among them. Deep one settlements that contain a deep one elder instead typically venerate that powerful deep one, who in turn serves one of the eldritch gods.

Underwater wielders. Deep ones prefer to fight with their claws. If they do resort to manufactured weapons, they prefer piercing ones, as these function best underwater. They can also use wands and staves; deep ones who pursue the study of more powerful magic often learn to create magic items for their weaker kinfolk to wield.

Immortal. A deep one does not age. Barring death from violence, disease, or misadventure, a deep one can live forever. Deep ones are immune to effects that cause magical aging.

Deep Dweller. Deep ones are immune to damage from water pressure; their bodies are capable of instantly adjusting to different water depths or even the surface with ease.

Deep One Bishop. Deep one bishops incite religious fervor in their kinfolk and promote their chosen deities as the greatest among the Outer Gods.

Hybrid Horrors. Deep one hybrids are the spawn of humans and deep ones. They are most comfortable with others of their kind, and typically cluster in small, insular settlements where they can assume positions of authority. They keep any humans within their towns subservient and cowed, making sure those other residents know better than to act against local laws. Though deep ones are devoutly religious, they usually cloak their true beliefs under a facade of more conventional worship, believing that by doing so they can avoid suspicion from visitors and nearby societies.

Section 15: Copyright Notice

Mythos Monsters (5E) © 2020, Legendary Games; Authors 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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