Deep One

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. Unlike skum, a similar aquatic race that reproduces with surface dwellers, 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.

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. Many deep ones gain levels as clerics, inciting religious fervor in their kinfolk and promoting their chosen deities as the greatest among the Outer Gods. Those few who instead choose to take up a less focused devotional path, such as that of an oracle, still venerate the Old Ones as a whole.

Deep ones seek out humans to kidnap and draw into their cults, and as breeding stock, producing a race of hybrid spawn of humans and deep ones. Hybrids 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.


  • Ability Score Modifiers: Deep one hybrids are hearty and devout but tend to be somewhat slow and awkward in their movements. They gain +2 to Constitution and Wisdom, but suffer -2 to Dexterity.
  • Type: Deep one hybrids are humanoids with the human and deep one subtypes.
  • Size: Deep one hybrids are Medium creatures and thus receive no bonuses or penalties due to their size.
  • Speed: A deep one hybrid’s base speed is 20 feet, as it walks with a shuffling gait. A deep one hybrid has a swim speed of 30 feet and gains a +8 racial bonus on all Swim checks.
  • Low-Light Vision: A deep one hybrid can see twice as far as a human in starlight, moonlight, torchlight, and similar conditions of dim light.
  • Natural Armor: A deep one hybrid’s thick skin and dense fatty tissues grant it a +1 natural armor bonus to AC.
  • Sea Longing: Every 24 hours a deep one hybrid spends in an area more than 10 miles from the sea, it must succeed at a DC 20 Will save or take 1 point of Wisdom drain.
  • Take to the Water: A deep one hybrid can hold its breath 10 times longer than a human can and gains a +2 bonus on Initiative checks and Reflex saving throws while swimming.
  • Final Change: A deep one hybrid ages at the same rate as a half-orc. 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, with the newly formed deep one gaining the following modifications to its physical ability scores: +6 Strength, –2 Dexterity, and +6 Constitution.
  • Languages: Deep one hybrids begin play speaking Aklo and Common. Hybrids with high Intelligence scores can choose from the following languages: Abyssal, Aquan, Dwarven, Elven, Giant, Gnome, Goblin, Halfling, Orc, and Undercommon. See the Linguistics skill page for more information about these languages.

Favored Class Options

The following favored class options are available to all deep one hybrid characters who have the listed favored class, and unless otherwise stated, the bonus applies each time you select the favored class reward.

Section 15: Copyright Notice

Mythos Monsters (PF1) © 2022, Legendary Games; Authors Jason Nelson, Jim Groves, Jonathan Keith, Tom Phillips, Alistair J. Rigg, and Greg A. Vaughan

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