Size/Type: Huge Outsider (Chaotic, Evil, Obyrith)
Hit Dice: 18d8+90 (171 hp)
Speed: 30 ft. (5 squares); fly 60 ft. (good)
Initiative: +2
Armor Class: 28 (+10 natural, +2 Dex, +8 deflection. -2 size), touch 18, flat-footed 26
Base Attack/Grapple: +18/+35
Attack: Tentacle +25 melee (1d8+14 plus stun)
Full Attack: 3 tentacles +25 melee (1d8+14 plus stun) or starbeam
Space/Reach: 15 ft./20 ft.
Special Attacks: Form of madness, improved grab, star beam
Special Qualities: Blindsense, DR 10/cold iron or good, frightful presence, regeneration, spell resistance 23, veil of horror, obyrith traits
Saves: Reflex +23, Fortitude +23, Will +23
Abilities: Str 29, Dex 15, Con 21, Int 8, Wis 7, Cha 10
Skills: Choose six
Feats: Awesome Blow, Improved Bull Rush, Improved Natural Attack, Improved Natural Armor, Power Attack, Powerful Charge, Snatch
Environment: The 885th layer of the Abyss
Organization: Solitary or battalion (3 - 5) or horde (12 - 15)
Challenge Rating: 15
Treasure: Double standard
Alignment: Always chaotic evil
Advancement - 19 - 21 HD (Huge); 22-26 HD (Gargantuan); 27+ (Colossal)
Spoiler
Show
The fiend you see before you is blurry and indistinct. It has the rough shape of a starfish the size of a small castle, with slick, oil-black flesh and five tendrils covered in wriggling cilia. Though it has no visible mouths, the air around it visible ripples with the sound of thousands of alien screams, all layered upon each other to form an anguished symphony.
Combat:
Blindsense (Ex): A tzitzimime can locate creatures within 60 feet by nonvisual means (a combination of hearing, scent, or by sensing vibrations).
Form of madness (Su): A creature within 60 feet that observes a tzitzimime must attempt a DC 19 Will save. Failure indicates that the creature's mind is flooded by hallucinations of the alien stars from which the demons originally came. The victim suffers a -4 profane penalty to attack rolls and saving throws made against that tzitzimime or its abilities; in addition, she cannot use arcane spells or spell-like abilities while within 30 feet of that tzitzimime. This condition can be lifted by heal, restoration, miracle, or wish. Any creature that makes this save, or has the negative effects of this ability healed by a spell, is immune to that particular tzitzimime's form of madness ability for 24 hours. This is a mind-affecting ability that does not affect chaotic evil outsiders. The save DC is Charisma base.
Frightful presence (Ex): Apart from its horrific form of madness, a tzitzimime can also unsettle foes with its mere presence. This ability takes effect automatically whenever the tzitzimime attacks, charges, or flies overhead. Creatures within 60 feet that have fewer HD than the tzitzimime must succeed on a Will save (DC 19) or be shaken for 1d6 rounds. This ability has no effect on other chaotic evil outsiders; creatures who successfully save against remain immune to the frightful presence of that tzitzimime for 24 hours.
Improved grab (Ex): If a tzitzimime hits with its tentacle attack, it can attempt to start a grapple as a free action without provoking an attack of opportunity. This ability can be used even against creatures that are the same size category as the tzitzimime.
Regeneration (Ex): Lawful- or good-aligned weapons inflict normal damage to a tzitzimime. A tzitzimime that loses a limb or a part of its body mass can regrow it in 1d6 rounds.
Starbeam (Su): Tzitzimimes arrived to the Abyss from the stars, and still draw some magic from their alien home. As a full-round action, a tzitzimime can fire a coruscating bolt of light at a single target within range (Reflex save DC 24 negates). This attack inflicts 4d6 points of force damage and 1d3 negative levels (DC 19 Will negates).
Stun (Su): Creatures struck by a tzitzimime's tentacle slam must succeed on a DC 24 Fortitude save or be stunned for 1d3 rounds.
Veil of horror (Su): The greatest demons may cloak themselves in the throbbing chaos of the Abyss. Due to the chaotic energy that swirls around them, any arcane divination spell that targets a tzitzimime has an 80% chance of failing.
revision: terminology fix ("axiomatic" to "lawful")