Epic Monsters: Yig, Father of Serpents (5E)

More Mythological Figures! Slithering scales and serpentine forms, make sure to keep your game table warm for today’s Epic Monster: Yig, Father of Serpents!


As far as I can tell--Lovecraft experts I SUMMON THEE!--this is one of the gods in the Cthulu mythos created by somebody else (Zealia Bishop) in a story that got a lot of rewriting from H.P. before publication (The Curse of Yig). He’s thought to be the same deity as Kukulcan and Quetzalcoatl, and depending on who you read might appear being worshipped by serpent men in Kull or Conan the barbarian’s enemies. Yig is vengeful and sneaky, either tricking people into committing terrible acts (like murdering a spouse covered by a snake-person illusion), transforming those who have wronged him into spotted snakes, or just killing folks. Fortunately while he’s quick to anger, Yig is apparently easy to please and cited in a few places as the most benign of the Great Old Ones.

Design Notes: There’s no PRD version of Yig to convert from the Pathfinder Roleplaying Game BUT one of my colleagues has become a golem and years ago he put together something I’m using to model our Father of Serpents (with great tips for incorporating Yig into your game). For anyone that doesn’t know Luis Loza yet he’s a time traveling game designer and one of the best I’ve had the pleasure to work with--it is a supreme pleasure to turn the chronal table on him for once. ;)

Yig, Father of Serpents

Huge aberration (great old one), chaotic neutral

Armor Class 25 (natural armor)
Hit Points 387 (25d12+225)
Speed 50 ft., burrow 40 ft., climb 60 ft., fly 30 ft., swim 60 ft.

25 (+7)​
30 (+10)​
28 (+9)​
22 (+6)​
21 (+5)​
25 (+7)​

Skills Deception +15, History +14, Insight +13, Nature +14, Perception +13, Survival +13
Damage Resistances acid, fire, lightning, necrotic; bludgeoning, piercing, and slashing from magical or adamantine weapons
Damage Immunities cold, poison, thunder; bludgeoning, piercing, and slashing from nonmagical weapons not made from adamantine
Condition Immunities charmed, diseased, frightened, paralyzed, petrified, poisoned
Senses blindsight 60 ft., darkvision 120 ft., truesight, passive Perception 23
Languages Deep Speech, Draconic, Giant, Sylvan; telepathy 200 ft.
Challenge 28 (120,000 XP)

Amorphous. Yig can move through a space as narrow as 5 feet wide without squeezing.

Amphibious. Yig can breathe air and water.

Call of the Serpent Father (1/long rest). Yig calls to his children to do his bidding. All snakes within 1 mile that have 6 hit dice or less arrive within 1 hour of the call. Additionally, 1d4 purple worms arrive within 1d6 rounds of this call. All creatures called in this manner follow Yig’s orders unquestionably for up to 24 hours, after which they return to their homes.

Immortality. When Yig is slain his body convulses, spraying poisonous acid for 1d4 rounds before the corpse explodes with snakes. Creatures that start their turn in or enter into the area make a DC 22 Dexterity saving throw or take 21 (6d6) acid damage plus 28 (8d6) poison damage. After the spraying ends, Yig’s body transforms into thousands of small snakes that flee in every conceivable direction (including burrowing). The snakes remain hidden for centuries, eventually reuniting to recreate Yig’s form. Any effect that destroys Yig’s body (such as disintegrate) prevents the spraying but nothing can stop the swarm of snakes.

Innate Spellcasting. Yig’s innate spellcasting ability is Charisma (spell save DC 23; spell attack +15). He can innately cast the following spells, requiring no material components:
Constant: speak with animals (snakes only), true seeing
At will: acid arrow, charm monster, command, dream, dimension door
3/day: dominate person, suggestion, symbol, teleport
1/day: dominate monster, geas, plane shift

Insanity. Any creature that attempts to interact directly with Yig’s thoughts (such as via detect thoughts or telepathy) must succeed at DC 23 Wisdom saving throw or gain an indefinite madness. When using his telepathy to communicate Yig doesn't activate this feature unless he spends an action to focus his mind on one opponent.

Legendary Resistance (3/Day). If Yig fails a saving throw, he can choose to succeed instead.

Magic Resistance. Yig has advantage on saving throws against spells and other magical effects.

Poison of Compulsion. A creature cannot be killed by Yig’s poison. Instead, a creature that would be dropped to 0 hit points becomes an unthinking being that strictly follows Yig’s command. The creature can only be liberated of this mental enslavement via a wish spell.

Rattle. A constant, mind-altering rattling surrounds Yig. This rattle can be heard up to 500 feet away. Any creature exposed to the sound of the rattling must succeed a DC 23 Wisdom saving throw or become compelled to approach the source of the sound. Creatures within 90 feet of the rattle must succeed on a second save or become charmed by it. While charmed in this way, the creature is incapacitated and has a speed of 0. The spell ends for a creature if it takes any damage or if someone uses an action to snap it out of the trance. Charmed creatures have disadvantage on saving throws against Yig. Offensive actions from Yig do not break this charm effect. Yig may silence his rattling at the start or end of his turn. Deaf creatures or creatures within areas of silence or similar effects are still able to perceive the rattling, but have advantage on saving throws made to resist it.

Regeneration. Yig regains 20 hit points at the start of his turn if he has at least 1 hit point. Yig dies only if he starts his turn with 0 hit points.

Serpent Sight. By concentrating, Yig can share the senses of any snake or serpentfolk within 1 mile of him, allowing him to see, smell, and hear as if he were that creature. These creatures are unaware of Yig’s presence or that they share their senses with him during this time. While he is sharing senses, Yig is still aware of his surroundings, but has disadvantage on Wisdom (Perception) checks (and a passive Perception of 19).


Multiattack. Yig uses his Unspeakable Presence then attacks three times (no more than once with his bite).

Bite. Melee Weapon Attack: +15 to hit, reach 20 ft., one target. Hit: 33 (4d12+7) piercing damage plus 28 (8d6) poison damage and the target is grappled (escape DC 24). In addition, at the start of each of the grappled target's turns, it takes 25 (4d8+7) bludgeoning damage. Yig can only grapple one Huge or smaller creature at a time.

Slam. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 25 (4d8+7) bludgeoning damage.

Spit. Ranged Weapon Attack: +15 to hit, range 30/120 ft., one target. Hit: 31 (6d6+10) acid damage plus 28 (8d6) poison damage.

Serpent’s Curse. Yig chooses a creature that he is able to see (including via Serpent Sight), transforming them into a snake. The creature must succeed on a DC 23 Wisdom saving throw or succumb to the curse, gaining snake-like features. At the end of every long rest, the creature must succeed on an additional DC 23 Wisdom saving throw or look more serpentine. After the creature has failed three of these additional saving throws, it instantly becomes a snake under Yig’s control. This snake form is immune to aging. The curse can only be alleviated by a wish spell or the intervention of another deity.

Shapechange. Yig magically polymorphs into a snake or serpent folk that has a challenge rating no higher than his own, or back into his true form. Yig only reverts to his true form if he dies. Any equipment he is wearing or carrying is absorbed or borne by the new form (Yig’s choice). In a new form, he retains his alignment, hit points, Hit Dice, ability to speak, proficiencies, Legendary Resistance, and Intelligence, Wisdom, and Charisma scores, as well as this action. Yig’s statistics and capabilities are otherwise replaced by those of the new form except any class features of that form.

Unspeakable Presence. Each creature of Yig’s choice within 300 feet of him and aware of him must succeed on a DC 23 Wisdom saving throw or gain a short-term madness. On a failure by 5 or more, the target gains a long-term madness instead, and on a failure by 10 or more, the target gains an indefinite madness instead. On a success, a creature is immune to Yig’s Unspeakable presence for 1 minute.

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Mike Myler

Mike Myler


not much hit points, my 7º lvl players carv out 300 hit point in 2 turns

mine can do about 230 in 2 turns, what is your point?

With 25 AC, resistance to almost all damage (effectively 774 hp), and regeneration it would to take my group about 15 rounds to take Yig to 0. I don't think they last that long though. Of course they would have a hard time with the DC 23 Unspeakable presence, Rattle, and Poison saves.

However, his damage is low, but I assume the legendary actions are missing - we will see.
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Unspeakable Presence. Each creature of Yig’s choice within 300 feet of him and aware of him must succeed on a DC 23 Wisdom saving throw or gain a short-term madness. On a failure by 5 or more, the target gains a long-term madness instead, and on a failure by 10 or more, the target gains an indefinite madness instead. On a success, a creature is immune to Yig’s Unspeakable presence for 1 minute.

I would suggest modifying the failures. As it stands, the more you fail, the less immediately threaten your madness (short-term madness has the most debilitating mechanical effects, indefinite madness is just an RP hook). I would suggest a cumulative effect: fail = short-madness; fail-5 =short-terms + long-term madness; fail-10 = short-term + long-term + indefinite madness


Hmm after a quick check I am getting a CR in the 25-26 range. Mostly because of the low damage (i'm getting a DPR of 195 at best), but is also depends on how you are calculating its effective HP. I am guessing you are assuming he has 2x the HP based on his resistances. This not what the DMG would have you do, but I see the logic. However, if that is the intent, I would prefer you just give him more HP.


Finally, I failed to mention that in general I like the build. I really like serpent's curse - it feels very Mythos appropriate.

I recently backed Peterson's Cthulhu for 5e kickstarter (should get the PDF in a few weeks) and I will be interested to see how his Mythos monsters compare to yours. It seems from the preview he is going outside of RAW more than you want to, but I think that is probably appropriate for Mythos Old Ones and such


My son has a Yig-worshipping PC gradually turning into Dragonborn Thulsa Doom, so this is great, thanks! Would probably use as an avatar of the god itself.

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