I love it. I know you usually don't mark down CR since it does indeed vary based off party composition, tactics, and builds. But if you had to around what CR would this be? I want to throw it against a party. They're currently in a setting that is eldritch horror themed.Today i bring the Great Old One Yig (Yig - PathfinderWiki). I build him by using the base PF1 version (Great Old One, Yig – d20PFSRD), the version of Luis Loza (Monstrous Physique — Yig, Father of Serpents | Know Direction) and my template Great Old One.
Yig, Father of the Snakes
Beyond Alignment (CN) Large monstrous humanoid (aquatic, chaotic, great old one, mythos, shapechanger)
Init +39 (always first); Senses blindsense 600 ft., darkvision 1.200 ft., divine senses (x10), greensight 600 ft., low-light vision, scent, serpent sight, true seeing; Perception +55
Aura cloak of chaos (DC 34), divine (410 ft., DC 26), fiery storm (100 ft., 3d4 divine damage), madness (410 ft., DC 41), rattle (500 ft., DC 41), unspeakable presence (300 ft., DC 41)
AC 91, touch 57, flat-footed 70 (+10 deflection, +15 Dex, +6 divine, +6 dodge, +10 insight, +34 natural)
hp 2.170 (31d20+465)x2; fast healing 20, regeneration 31 (elder sign or epic and lawful)
Fort +59, Ref +59, Will +53
Defensive Abilities all-around vision, amorphous, beyond morality, dimensional mastery, foresight, freedom of movement, hyperdimensional body, immortality, lesser cosmic firmament, mad mind (DC 41), messiah of snakes, sixth sense; DR 30/epic and lawful; Immune ability damage and drain, acid, aging, cold, death effects, disease, energy drain, mind-affecting effects, paralysis, petrification, poison, damage from non-magical weapons, death fro massive damage, Terrestrial and Stellar Hazards; Resist fire 30, Dimensional Hazard; PR/SR 47, any power or spell which fails to penetrate Yig resistance is reflected back upon the caster
Speed 180 ft., climb 180 ft., swim 180 ft.; air walk, reality shift, greater starflight (2d6)
Melee bite +72 (8d10+27 plus grab and poison), 2 claws +72 (4d10+27/19–20), tail slap +72 (4d10+27 plus grab)
Ranged lesser gamma ray burster +63 touch (15d20 half fire half divine damage) or venomous spit +63 touch (40d10 acid plus special)
Space 10 ft.; Reach 10 ft. (20 ft. with tail slap)
Special Attacks alter reality, call of the serpent father, constrict (4d10+21), curse of Yig (DC 41), dimensional rip (DC 41), mythic power (10/day, surge +1d12), nova (DC 46), poison (DC 46), rend (2 claws, 4d10+27), serpent’s curse (DC 41), serpentine dreams (DC 41), swallow whole (8d10+27 damage plus 15d6 acid damage, 27 AC, 217 hp), unnamable doom
Spell-Like Abilities (CL 37th; concentration +53)
Constant—air walk, cloak of chaos (DC 34), foresight (self only), freedom of movement, mind blank, speak with animals (reptiles only), tongues, true seeing
At will—ancient sorcery of serpentfolk, animal shape (snakes only), astral projection, awaken (snakes only), baleful polymorph (DC 31, into harmless snakes only), charm animal (DC 27, snakes only) charm monster (DC 30), command (DC 27), commune with nature, control weather (as a druid), curse of yig (DC 33), demand (DC 34), dimension door, dominate monster (DC 35, snake and snake-like only), dream council, dream scan, dream voyage, fire snake (DC 31), greater dispel magic, greater teleport, insanity, interplanetary teleport, mind thrust VI (DC 32), nightmare (DC 31), overwhelming poison, plane shift (DC 33), pocketful of vipers (DC 28), poison (DC 30), psychic crush V (DC 35), reverse gravity, sending, sepia snake sigil (DC 29), snake staff (DC 32), suggestion (DC 29), summon monster IX (mythos only), summon nature’s ally IX (snakes only), summon king snake, sundered serpent coil, transport via plants
3/day—dominate monster (DC 35), feeblemind (DC 31), gate, geas/quest, heal, maze of madness and suffering, weird (DC 35), wish
1/day—implosion (DC 35), microcosm (DC 35), symbol of persuasion (DC 32), summon (level 9, mythos creatures with total base HD not superior of double the great old one HD 100%), time stop, true resurrection
Str 38, Dex 40, Con 41, Int 30, Wis 33, Cha 30
Base Atk +31; CMB +66 (+68 sunder); CMD 103 (105 vs. sunder)
Feats Alertness, Combat Reflexes, Dodge, Great Fortitude, Greater Sunder, Greater Vital Strike, Improved Initiative, Improved Sunder, Improved Vital Strike, Mythos SummonerB, Power Attack, Vital Strike
Epic Feats Good Fortitude, Improved Dodge, Sixth Sense, Superior Initiative
Skills All skills 40 + ability modifier
Languages Aklo, Common, Draconic, Druidic, Serpentfolk, Undercommon; speak with animals (reptiles only), telepathy 100 ft.
SQ amphibious, change shape (any serpentine form; shapechange) [this replace unspeakable form], compression, devastating, ignore reality, lesser constant insight, madness sovereing, maven, might, omnicompetent, otherworldly insight, snake empathy +47, virtual size category +1, unspeakable grip
Yig renounce to the integrated class feature for double the divine slot
• Amaranthine Mind (Ex): Con as circumstance to attack rolls
• Amaranthine Soul (Ex): Con as circumstance to saving throw
• Devasting Strike (Ex): Your attack is particularly devastating
• Perfect Initiative (Ex): Always first
• Self Mastery (Ex): You can separate your individual appendages
• Seventh Sense (Ex): You can replay a number of rounds per day equal to your divine rank
Cosmic Abilities (esoteric)
• Abrogate (Su): Any single opponent within your divine aura has its greatest ability negated
Double Chaos Portfolio Traits (Demi-Deity)
Granted Power: You cast chaos spell at +1 caster level
• Transmutation Immunity (Su): You are immune to transmutation based attacks
• Transmutation Reflection (Su): Reflect any transmutation attack within your divine aura/realm
• Greater Scion of Chaos (Ex): +12 competence bonus on attack rolls, damage rolls and armor class while you are within a chaos aligned locale
• Perfect Summoning (Chaos) (Ex): Chaotic creatures summoned have 200% more HD
• Greater Taint of Chaos (Su): Healing against your damage 25% effective except in lawful aligned locale
Double Snake Portfolio Traits (Demi-Deity)
Granted Power: You gain a primary natural bite attack that deals 1d6 plus your Str modifier with the grab ability (for Medium size). If you already have a bite attack, instead that attack increase its damage by one size and gains the grab ability.
• Maw of the Snake (Ex): You gains the swallow whole ability with the same damage of your bite plus 1d6 acid damage/2 HD
• Poison Immunity (Su): You are immune to poison
• Snake Hunting Ground (Ex): +12 competence bonus on attack rolls, damage rolls and armor class while in an area with 80 degrees Fahrenheit or warmer
• Perfect Summoning (snake) (Ex): Snakelike creatures summoned have 200% more HD
• Toxic (Su): Immunities against your poison ineffective
Alter Reality (Su)
A great old one ignore the reality. Once per hour, as a standard action, Yig can duplicate any 9th level spell. This ability can also duplicate any epic spells of a DC equal or less of 70. Other use of this ability are GM’s discretion.
Call of the Serpent Father (Su)
Once per day, Yig may call to his children to do his bidding. As a full-round action, Yig calls all snakes and snake-like creatures with 25 HD or fewer and without Divine Rank within 10 miles radius. A creature with an Intelligence score of 4 or more can make a Will save DC 41 for negate this ability. These creatures arrive within 1 hour of the call. All creatures called in this manner follow Yig’s orders unquestionably for up to 24 hours, after which they return to their homes. Creatures binded to others (like a druid animal companion) always gains a saving throw for negate this ability and add their companion Charisma modifier (if positive) as a bonus on the saving throw. This is a compulsion, mind-affecting effect. The save DC is Charisma-based.
Curse of Yig (Su)
Once per round as a free action when he touches or damages a creature with any natural attack, Yig can target that creature with a potent curse. The target must succeed at a DC 41 Will save or it takes a –6 penalty on all saving throws against poison effects and loses the ability to recover from poison effects naturally (though magical effects that remove poison effects still work). The cursed creature cannot gain the benefit of immunity to poison, be it from a class or racial ability, a magic item, or any other source. As long as it suffers under the curse of Yig, the victim becomes staggered for 1d6 rounds whenever it fails a saving throw against a mind-affecting or poison effect, and any offspring sired or birthed are deformed in some hideous (but mostly cosmetic) fashion. This is a curse effect. The save DC is Charisma-based.
All of Yig’s natural attacks are primary attacks that add 1-1/2 his Strength modifier to their damage. Yig ignores hardness less than 21 for any object he strikes.
If Yig is slain, he explode with nova as normal, but he does not stay dead for long. He is reborn 3 months after his death, hatching from the egg of a venomous serpent (although not necessarily on the same planet on which his previous incarnation was slain). He spends a year in the form of a venomous (but otherwise normal) snake, after which he sheds his skin and emerges once again as Yig. Typically, Yig does not hold grudges against those who slew him, but this is not always the case.
Messiah of Snakes (Su)
Snake and snake-like creatures without DR cannot take hostile actions against Yig. All other snake and snake-like creatures have a starting attitude of friendly against Yig.
Yig deals d10's for base damage dice of all melee, natural weapon, and unarmed attacks with virtual size categories, and his damage dice cannot go below this dice but this cannot increase to more dice than his HD.
Yig has Mythic Power (10/day, Surge +1d12) and counts as a 10th-rank Mythic creature. Yig One can use any of his spell, spell-like abilities and Alter Reality effects as the Mythic versions of those spells (if a Mythic version of that spell exists), expending Mythic Power as normal. He can also expend Mythic Power to use the augmented versions of these spell, spell-like abilities and effects.
Bite or venomous spit—injury; save Fort DC 46; frequency 1/round for 10 rounds; effect 1d6 Strength and Constitution drain plus nauseated for 1 round; cure 3 consecutive saves. A creature killed by this poison explode in a bubble of acid that deal 10d6 acid damage in a 20 ft. radius (Reflex DC 46 half the damage). From this bubble spawn 4d6 snake swarms. The save DC is Constitution-based.
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 41 Will save 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 fascinated for 2d6 rounds. Creatures fascinated receive a –4 penalty to save against any effects create by Yig. Offensive actions from Yig do not break this fascination. Yig may silence this rattling as a free action. Deaf creatures or creatures withing areas of silence or similar effects are still able to perceive the rattling, but receive a +8 bonus to save against this effect. The save DC is Charisma-based.
Serpent’s Curse (Su)
As a full-round action, Yig may curse a creature within 120 ft. to transform into a snake. The creature must succeed on a DC 41 Will save or succumb to the curse, gaining snake-like features. The creature immediately receives 2 Intelligence drain. Every week, the creature must succeed on another DC 41 Will save or receive an additional 2 ability drain to the same scores and slip further into the appearance of a snake. When this Intelligence drain would reduce the victim’s Intelligence score below 2, the victim is instead transformed (as if via baleful polymorph) into a Tiny venomous snake under Yig’s control. This snake form is immune to aging. The curse and its ability drain can only be alleviated by a creature with DR. This is a curse, polymorph effect. The save DC is Charisma-based.
Serpent Sight (Su)
By concentrating, Yig can share the senses of any snake or snake-like within 10 miles 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. A creature with Intelligence of 4 or higher or DR can make a Will save DC 41 for negate this ability. A creature that succeed the save, is immune to this ability for 24 hours. A creature is unaware of making this save. While he is sharing senses, Yig is still aware of his surroundings, but receives a –8 penalty to any Perception checks. The save DC is Charisma-based.
Serpentine Dreams (Su)
Any creature that has ever willfully harmed a snake, has suffered the effects of the curse of Yig (see above), or has slain one of Yig’s cultist can be targeted by the Great Old One’s serpentine dreams, regardless of the distance between the creature and Yig—even across planar boundaries. In order to use serpentine dreams against a target, Yig must first successfully affect the target with his nightmare spell-like ability. If the victim fails its save against nightmare, it must succeed at a DC 41 Will save or take 2d6 points of Intelligence drain in addition to the normal effects of nightmare. When this Intelligence drain would reduce the victim’s Intelligence score below 2, the victim is instead transformed (as if via baleful polymorph) into a Tiny venomous snake. This is a curse, mind-affecting, polymorph effect. The save DC is Charisma-based.
Snake Empathy (Ex)
This ability functions as a druid’s wild empathy, save that it works only on snake and snake-like creatures despite type and Intelligence score. Yig gains a racial bonus on this check equal to his Hit Dice.
Unspeakable Presence (Ex)
Failing a DC 41 Will save against Yig’s unspeakable presence causes the victim to become more susceptible to curse effects. The victim takes a –6 penalty on all saving throws against curse effects, and the effective DC to remove a curse from such a victim increases by 6. A creature normally immune to curses that is affected by Yig’s unspeakable presence can now be affected by curses (but takes no further penalty against curses as a result of the Great Old One’s unspeakable presence). This effect lasts for 1 year or until removed by a miracle or wish. If a creature suffering from this effect dies and is brought back to life, there is a 50% chance the effect persists upon the creature’s restoration to life.
Venomous Spite (Ex)
As a standard action Yig can spit a handful of poison as a ranged touch attack with a range of 120 ft. and no range increment. A creature hit must make a Fortitude save DC 46 or is permanently blinded and come into contact with the poison (it must immediately make a save against the poison). The save DC is Constitution-based.