Sibriex

Thought to be as old as the Abyss itself, sibriexes haunt remote parts of the plane, where they use their vile abilities to breed new horrors and apprehend forbidden lore. Rivulets of blood and bile cascade from a sibriex's body. Where these noxious fluids hit the ground, the landscape becomes polluted.
Keepers of Forbidden Lore. Sibriexes have spent eons amassing information from across the planes, hoarding knowledge for when it might be useful. Such is their incredible intellect that many seek them out, including demon lords. Some sibriexes act as advisors and oracles, manipulating Demons and Devils into serving their ends, while other sibriexes cling to their secrets, parceling out lore only when doing so would advance their plans.
Fiend Crafters. Sibriexes can channel the power of the Abyss to create new demons from other creatures. Over the course of days, they can create vast numbers of rutterkins to protect their lands and to ensure that the plane teems with destructive monsters. Some demons petition sibriexes for physical gifts, and if they are moved to do so, sibriexes can graft on new body parts to give the demons greater strength, vision, or stamina. Sibriexes never give aid freely; they demand a service or a treasure in return for the flesh-shaping they provide.
Variant: Flesh Warping Creatures that encounter a sibriex can be twisted beyond recognition. Whenever a creature fails a saving throw against the sibriex's Warp Creature effect, you can roll percentile dice and consult the Flesh Warping table to determine an additional effect, which vanishes when Warp Creature ends on the creature. If not removed, the effect becomes a permanent feature of that body.
A creature can willingly submit to flesh warping, an agonizing process that takes at least 1 hour while the creature stays within 30 feet of the sibriex. At the end of the process, roll once on the table (or choose one effect) to determine how the creature is transformed permanently.

Genetic Descendants

• Gibbering Mouther
• Lemure
• Rutterkin

Related Ethnicities

• Abyss Natives

Sibriex

Huge fiend, chaotic evil

Armor Class 19 (natural armor)

Hit Points 150 12d12+72

Speed Fly: 20ft

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STR

10 0

DEX

3 -4

CON

23 +6

INT

25 +7

WIS

24 +7

CHA

25 +7

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Saving Throws Int +13, Cha +13

Skills Arcana +13, History +13, Perception +13

Damage Resistances cold, fire, lightning; bludgeoning, piercing, and slashing from nonmagical attacks

Damage Immunities Poison

Condition Immunities poisoned

Languages all, telepathy 120 ft.

Challenge 18

Contamination. The sibriex emits an aura of corruption 30 feet in every direction. Plants that aren't creatures wither in the aura, and the ground in it is difficult terrain for other creatures. Any creature that starts its turn in the aura must succeed on a DC 20 Constitution saving throw or take 14 (4d6) poison damage. A creature that succeeds on the save is immune to this sibriex's Contamination for 24 hours.
Innate Spellcasting. The sibriex's innate spellcasting ability is Charisma (spell save DC 21). It can innately cast the following spells, requiring no material components:
At will: charm person, command, dispel magic, hold monster
3/day: feeblemind
Legendary Resistance (3/Day). If the sibriex fails a saving throw, it can choose to succeed instead.
Magic Resistance. The sibriex has advantage on saving throws against spells and other magical effects.
Hover. If knocked prone while flying, the creature doesn't fall, and it can stop moving in midair and not fall.

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Actions

Multiattack. The sibriex uses Squirt Bile once and makes three attacks using its chain, bite, or both.
Chain. Melee Weapon Attack: +6 to hit, reach 15 ft., one target. Hit: 20 (2d12 + 7) piercing damage.
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 9 (2d8) piercing damage plus 9 (2d8) acid damage.
Squirt Bile. The sibriex targets one creature it can see within 120 feet of it. The target must succeed on a DC 20 Dexterity saving throw or take 35 (10d6) acid damage.
Warp Creature. The sibriex targets up to three creatures it can see within 120 feet of it. Each target must make a DC 20 Constitution saving throw. On a successful save, a creature becomes immune to this sibriex's Warp Creature. On a failed save, the target begins to transform. The transformation works like polymorph other, except it allows the shape to be any that the sibriex can imagine (whether such a creature actually exists in that form or not). For example, the sibriex could turn a wolf into a human with purplish black skin and tentacles for arms. The DM can choose an effect or roll on the Flesh Warping table below. They must repeat the saving throw at the start of each of their turns, ending the effect after three successful saves. Each failed save causes an additional step of transformation, and they must make an additional Constitution saving throw or gain a level of exhaustion. If they gain six levels of exhaustion, they collapse into a pile of fleshy goo, from which they will emerge as a living rutterkin, lemure, gibbering mouther or similar creature under the sibriex's control. The transformation of the body can be undone only by a wish spell.

Legendary Actions

The sibriex can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The sibriex regains spent legendary actions at the start of its turn.
Cast a Spell. The sibriex casts a spell.
Spray Bile. The sibriex uses Squirt Bile.
Warp (Costs 2 Actions). The sibriex uses Warp Creature.

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d100	Flesh Warping Effect
01-05	The color of the target's hair, eyes, and skin becomes blue, red, yellow, or patterned.
06-10	The target's eyes push out of its head at the end of stalks.
11-15	The target's hands grow claws, which can be used as daggers.
16-20	One of the target's legs grows longer than the other, reducing its walking speed by 10 feet.
21- 25	The target's eyes become beacons, filling a 15-foot cone with dim light when they are open.
26- 30	A pair of wings, either feathered or leathery, sprout from the target's back, granting it a flying speed of 30 feet.
31-35	The target's ears tear free from its head and scurry away; the target is deafened.
36-40	Two of the target's teeth turn into tusks.
41-45	The target's skin becomes scabby, granting it a +1 bonus to AC but reducing its Charisma by 2 (to a minimum of 1).
46-50	The target's arms and legs switch places, preventing the target from moving unless it crawls.
51-55	The target's arms become tentacles with fingers on the ends, increasing its reach by 5 feet.
56-60	The target's legs grow incredibly long and springy, increasing its walking speed by 10 feet.
61-65	The target grows a whiplike tail, which it can use as a whip.
66-70	The target's eyes turn black, and it gains darkvision out to a range of 120 feet.
71-75	The target swells, tripling its weight.
76-80	The target becomes thin and skeletal, halving its weight.
81-85	The target's head doubles in size.
86-90	The target's ears become wings, giving it a flying speed of 5 feet.
91-95	The target's body becomes unusually brittle, causing the target to have vulnerability to bludgeoning, piercing, and slashing damage.
96-00	The target grows another head, causing it to have advantage on saving throws against being charmed, frightened, or stunned.