(from Planescape: Morte's Planar Parade - 2023):

Arachnid predators of the Shadowfell, darkweavers inhabit caves, dungeons, and other dark locales throughout the multiverse, including Undersigil and the windswept darkness of Pandemonium. A darkweaver lurks in the shadows of its lair, waiting for hapless prey to pass by. When a target approaches, the darkweaver fires webs of pure shadow at its quarry, then drags the victim into the darkness.

Darkweavers are fascinated by sensations—particularly taste—and how creatures from across the planes experience reality. For them, the act of eating is an experience to be drawn out and savored, with every meal considered in all its facets. Whether its fare is a demon, an archon, a struggling halfling, or a catatonic mule, all such meals are culinary delights for a darkweaver, served up from the cosmic kitchen that is the multiverse. These spider-like terrors appreciate second-hand descriptions of sensations, especially those they’re unlikely to experience in their home environment. A darkweaver’s captive might delay being consumed by sharing tales of its experiences, particularly great meals, with the monster. Some might even convince a darkweaver to release them if they promise to return with rare spices or one-of-a-kind meals. Those who manage to escape a darkweaver should think twice about returning to the creature’s lair, though, as darkweavers prioritize their appetites over bargains.

A Darkweaver's Lair:

Darkweavers dwell in lightless caverns, preferring locations touched by pitch-black planes, such as Pandemonium or the Shadowfell. Darkweavers tend to inhabit isolated sites where they can weave webs of shadow undisturbed.

A darkweaver encountered in its lair has a challenge rating of 11 (7,200 XP).

Lair Actions:

On initiative count 20 (losing initiative ties), a darkweaver can take one of the following lair actions; the darkweaver can’t take the same lair action two rounds in a row:

Extinguish. All nonmagical flames within 30 feet of the darkweaver are extinguished. In addition, if this area overlaps with an area of light created by a spell of 2nd level or lower, the spell that created the light is dispelled.

Shadow Fears. The darkweaver instills frightful magic into its webs. Each creature grappled by the darkweaver’s Shadow Web must make a DC 15 Wisdom saving throw. On a failed save, the creature has the frightened condition until the end of its next turn.

Shadow Step. If the darkweaver is in dim light or darkness, it teleports, along with any equipment it is wearing or carrying, to an unoccupied space it can see within 60 feet of itself that is in dim light or darkness.

Darkweaver Webs:

A darkweaver’s web has a 50 percent chance of having (1d100) cocoons. Roll on the Darkweaver Cocoon Contents table to determine what might be inside each of these shadowy masses.

Darkweaver Cocoon Contents:

d6    Category

1      Roll a die. If you roll an even number, the cocoon contains the bones of a Humanoid. If you roll an odd number, the cocoon contains the bones of a non-Humanoid creature, such as a flumph or a mule.

2      A swarm of insects that might be a darkweaver’s young

3      A corpse holding a jar of universal solvent with a slightly stuck lid

4      A collection of menus from restaurants in Sigil

5      (1d6) gold pieces amid a digested slurry

6      A halfling commoner or musteval guardinal that the darkweaver forgot about

(from Fiend Folio - 2003):

Darkweavers are sinister and alien beings from the Plane of Shadow that have found that the Material Plane offers far more plentiful hunting grounds than their home. Relatively new arrivals to the Material Plane, the darkweavers seek to learn more about the Material Plane and the power of the creatures that reside there so that they can make a bid for control. 

Few creatures that have seen a darkweaver truly understand what it looks like. Every darkweaver resides in a thicket of writhing, supernatural shadows, and a creature must delve into the benighted depths of this darkness to find it. At the center of this area, a curious explorer might catch a glimpse of a spiderlike form that is wreathed in protective shifting darkness. 

The true form of a darkweaver resembles a spider in only in the vaguest fashion. Its fleshy, gray-skinned body is divided into two segments, each with four tentacles. Clusters of spiderlike eyes cover all sides of its front section, and the underside contains a mouth with deadly fangs. A darkweaver usually walks on all eight tentacles, but it can rear its front section up and move about, which frees its front tentacles to attack foes or manipulate objects. 

Darkweavers speak Abyssal, Common, and Infernal.

COMBAT: A darkweaver relies heavily on its ability to shroud the battlefield in a web of shadow. Capable of seeing through the shadows it creates, a darkweaver prefers to hide in the effect and lure prey in with suggestion. If prey refuses to enter the shadow strands, a darkweaver relies on darkness and confusion to make the creature hesitate while it moves the area of shadow strands over it. When a creature is close to the center of the effect, the darkweaver rears up and lashes out with its front four tentacles, hoping to ensnare the foe and sap its strength. 

Improved Grab (Ex): If a darkweaver hits an opponent that is at least one size category smaller than itself with a tentacle rake attack, it deals normal damage and attempts to start a grapple as a free action without provoking an attack of opportunity (grapple bonus +9). If it gets a hold, it automatically hits with its bite, dealing 1d6+3 points of damage and 2d4 points of Strength damage. Thereafter, the darkweaver has the option to conduct the grapple normally, or simply use its tentacle to grapple the opponent (–20 penalty on grapple check, but the darkweaver is not considered grappled). In either case, each successful grapple check it makes during successive rounds automatically deals bite damage. 

Shadow Strands (Su): At will, a darkweaver can create an aura of weblike, supernatural, semisolid shadow that emanates outward from it in a 60-foot spread. A darkweaver can see normally through the shadow strands, but other creatures have great difficulty doing so. Each full 5 feet of shadow strands grants one-quarter concealment. Thus, a creature in the shadow strands 10 feet away from another creature would have one-half concealment, and a creature in the shadow strands 20 feet away would have total concealment. A creature in the shadow strands has no concealment from creatures within 5 feet. Creatures with darkvision suffer these effects, and the shadow strands even baffle blindsight, but true seeing allows a creature to see normally through them. 

Any creature that enters this area can freely move toward the darkweaver, but any attempt to move in any other direction is resisted by the semisolid shadow strands. A creature attempting to move in such a fashion must make a Strength check or an Escape Artist check; the creature can move away from the darkweaver 5 feet for each full 5 points by which the check result exceeds 10. If a creature is adjacent to the darkweaver (within 5 feet), it can move freely so long as it remains adjacent to the darkweaver. A creature protected by a freedom of movement spell is immune to the constraining effects of the shadow strands. 

The darkweaver can move about as it wishes and bring the area of shadow strands with it. Creatures are not affected by the darkweaver’s moving the strands, but the direction toward the darkweaver will likely change. 

Creatures within the strands do not need to guess in which direction the darkweaver lies; it becomes immediately obvious when they try to move away and the shadow strands snarl and twist to block all other routes. When a creature without freedom of movement attempts to move against the strands, the darkweaver is immediately aware of its location even if it cannot see the creature due to invisibility. 

Darkweavers are immune to other darkweavers’ shadow strands and can see through them. 

Spell-Like Abilities: 3/day—confusion, darkness, suggestion, tongues, web; 1/day—shadow walk. Caster level 13th; save DC 13 + spell level. 

Strength Damage (Su): Any creature bitten by a darkweaver takes 2d4 points of Strength damage (or 4d4 points on a critical hit). Darkweavers “eat” by sapping a victim’s strength. 

All-Around Vision (Ex): A darkweaver can see in all directions at once. Because of this, it has a +4 racial bonus on Search and Spot checks, and it cannot be flanked. 

Fast Healing (Ex): As long as it has at least 1 hit point, a darkweaver regains lost hit points at the rate of 3 per round. Fast healing does not restore hit points lost from starvation, thirst, or suffocation, and it does not allow a darkweaver to regrow or reattach lost body parts.

Shadow Jump (Su): A darkweaver can travel between shadows as if by means of a dimension door. The limitation is that the magical transport must begin and end in an area with at least some shadow. The darkweaver can shadow jump up to a total of 320 feet per day; this amount can be split up among many jumps in 10-foot increments. Thus, a darkweaver that shadow jumps 35 feet would use up 40 feet of its shadow jump limit for the day. 

A darkweaver in its shadow strands always has enough shadow to jump from unless a light source as bright as a daylight spell is brought within 5 feet of it. 

Shadowstuff Armor (Su): A darkweaver is shrouded in a semisolid armor of shadowstuff that grants it a +4 deflection bonus to Armor Class and a +10 circumstance bonus on Hide checks (included in the statistics above). The shadowstuff armor does not provide concealment, nor does it provide the requisite shadows to make a shadow jump. This armor disappears in an antimagic field, but it returns as soon as the darkweaver is out of the field. 

Sunlight Vulnerability (Ex): When exposed to sunlight or to light equivalent to a daylight spell, a darkweaver takes a –2 morale penalty on all attacks, saves, checks, and damage rolls. In addition, it does not regain hit points from its fast healing ability. 

A darkweaver’s shadow strands provide the creature with total concealment from light that is outside the shadow strands’ area. Any magical light source within the shadow strands must be within 5 feet of the darkweaver to affect it because of the concealment the shadow strands provide. 

Tentacle Regeneration (Ex): Foes can attack a darkweaver’s tentacles, but only when those appendages are actually holding an opponent. A tentacle has an AC of 27 (touch 19) and can withstand 20 points of damage. The loss of a tentacle does not harm the creature (that is, the damage does not apply against its hit point total), and it regrows the limb within a day.

Skills: A darkweaver has a +8 racial bonus on Climb checks and can always choose to take 10 on Climb checks, even if rushed or threatened. 

Darkweaver Society: Darkweavers are loners by nature, but they often keep dangerous predators as “pets.” When a darkweaver saps all of a creature’s strength (reducing its Strength score to 0 and rendering it helpless), it often carries the creature away and locates a large carnivore or a tribe of evil creatures willing to eat its catch. The darkweaver then ensnares the predator in its shadow strands, forcing the predator to move toward it. When it comes close, the darkweaver drops its still-living prey as a reward and steps back, allowing the creature to feed on the weakened foe. The darkweaver repeats this activity several times until the predator comes to rely on it for food and views it as an ally. The darkweaver’s tongues and suggestion abilities often help to cement this relationship. Darkweavers’ lairs are often guarded by such predators, and it isn’t unknown for a tribe of predatory creatures, such as trolls, to come to worship a darkweaver and aid it as it pursues its dreams of dominance over others.

(from Planescape Monstrous Compendium Appendix. II - 1995):

The darkweaver’s a strange and frightening creature, partly real and partly shadow. It dwells in the caves and grottos of some of the chaotic planes, particularly Pandemonium. Some cutters say the thing’s native to the Demiplane of Shadow, and that it settled in this corner of the planes because it found conditions in the Abyss and Pandemonium to its liking. Not many sods’ve ever gotten a chance to question a darkweaver about its origins, and few of these even survived the experience.

The darkweaver creates webs of gloom and shadow just like a spider casts webs of silk. Its snares aren’t easily detected, since it prefers to air in places where daylight never comes. A darkweaver’s net an stretch for miles through twisted tunnels and dank caverns, trapping luckless sds onestradat a time until they’ve hopelessly cpught in its shadow. In its web, the darkweaver can manipulate the thoughts and emotions of its vitims until thes willingly walk into its dark embrace.

The darkweaver’s form is amorphous and menacing, gliding like black oil over a cavern wall or pooling in places where the shadow is deepest. Folds of darkness cling to ir like a cloak or a second skin. If the darkness surrounding it can be dispelled, the darkweaver’s body is revealed to be a rubbery, spherical thing with strong wiry tentacles and shorter, thicker feeding proboscises. It’s said that a body’d rather meet the Lady of Pain than see a darkweaver in the light.

Combat: The darkweaver tries to lure its victims into its web of shadow, or failing that, to weaver its web around them and prevent their escape. If the darkweaver’s removed from its surrounding shadows, it flees as quickly as possible. The creature can’t abide the touch of bright light.

The darkweaver’s web can extend for hundred of yards. The outermost strands appear to be insubstantial at first; a basher can brush his hand right through one and feel only an eerie, oily chill. Shining a light on the web makes the strands fade into mere shadows, but they don’t fade right — they seem to slither away like snakes. The weaver blends the edges of its web into surrounding natural shadows perfectly; there’s only a 10% chance that a character notices the outer strands beforehe enters the web. (Rangers, experienced guides, or creatures with unusual acute senses have a 30% chance to detect the darkweaver’s web).

Inside the outer layers of the web, vision drops to half normal. The shadowy strads easily give way to a creature moving toward the center, but a sod trying to get out finds that the shadowy strands don’t retreat from his lihgt anymore; they cling to him and prevent his escape. Any creature trying to leave the web is reduced to half its normal movement and must successfully make a saving throw vs. spell to force its way through the shadowy strands.

If a sod enters the inner part of the web (usually an area about 100 yards across), he’s caught for sure. Again, he’s free to move toward the web’s center, but to move back out he must successfully make a saving throw vs. spell or become disoriented and slowed. No matter which way e turns, he travels deeper toward the center. Even if the character makes a successful saving throw, he’s still slowed. The darkweaver’s web is thick enough to swallow any normal light, and vision’s reduced to one-quarter normal. A lantern that casts a beam 60 feet illuminates a path only 15 feet long in the inner part of the web.

At the web’s center, victims must successfully save vs. spell or become held. Even if they do succeed, they are still slowed and can’t escape the center without killing the darkweaver or dispelling its web. The darkweaver’s lair is here, and the web’s center is as dark as the blackness of a darkness spell.

If the weaver can’t entice a sod into entering its web, it may try to misdirect him into a passage it can close behind him, or get ahead of him and web the path he’s using. A darkweaver can create one 10’ cube of gloomweb per round; if it webs the same area twice, the thickness is equal to the inner part of its web, and a third time results in webbing as thick as what lies at the center of the darkeaver’s web.

Once per round, the darkweaver can use the spell-like powers of confusion, sleep, or suggestion with a range of 60 feet. In any area of shadow or darkness, the darkweaver can become invisible, create 2 to 5 mirror images, or teleport up to 200 feet to another area of shadow. In addition, the creature can create shades, solid fog, or a symbol of despair once per day while it’s in its own web. Darkweavers communicate by means of a limited form of telepathy with a 60-foot range; humans and demihumans perceive the creature’s thoughts as sibiliant whisperings in the shadows.

The darkweaver uses its powers to immobilize its victims before drawing them near enough to feed. If possible, it attacks physically only when its victims arehopelessly entangled in the center of its web. The weaver attacks by lashing at its victims with its tentacles for 1d2 points of damage each; if it can hit a victim with at least four tentacles, it draws near enough to insert its feeding proboscises. These automatically inflict 2d4 points of damage per round, and the victim must successfully save versus spell or permanently lose 1 point of Constitution in each round of feeding. The darkweaver’s victim can fight back only by trying to break free or attacking with a Type S weapon.

A weaver’s forced to release a victim it has grasped of ot takes more than 15 points of damage, if the victim succeeds in a bend bars/lift gates roll, or if the darkweaver is struck with magical light of some kind.

The darkweaver’s vulnerable to light-based attacks. A light spell destroy a 10’ cube of its web and inflicts 1d3 points of damage on the creature before dissipating. A continual light destroys 1d6 10’ cubes of the creature’s web, dispels its shadow protection for 1 rpund, and inflicts 1d6 points of damage. Very powerful light effects such as a sunray or the sunburst effect of a wand of illumination inflict 2d10 points of damage, destroy 2d6 10’ cubes of the web, and dispel the darkweaver’s shadow for 1d6 hours. (The Armor Class and magic resistance in parentheses note the darkweaver’s defenses without its shadow protection.)

Habitat/Society: The darkweaver haunts subterranean passageways, gloomy forests, and dismal swamps throughout the Abyss, Pandemonium, and Limbo. It’s also been rumored that great numbers of the creatures dwell on the Demiplane of Shadow. The darkweaver is asexual and reproduces by division, although this is a very rare occurence. A sod who runs across a darkweaver that’s just divided should be aware that the young creature’s a 3 HS version of its parent.

Darkeavers’re diabolical creatures that use any means available to lure potential pery into their webs. When dealing with intelligent creatures, the weaver’s likely to say or promise anything to get its prey to come nearer. They’re clever enough to leave formidable prey such as greater tanar’ri alone, and may strike deals with more powerful neighbors. Darkweavers are patient and calculating creatures, and may let a meal go today if it means having two meals tomorrow.

Ecology: The darkweaver preys on anything that comes near its web, but has the sense to leave very tough creatures alone. If anything strong enough to kill it enters its web, the darkweaver is likely to use its powers of illusion and deceit to hide from its attacker until it’s safe again. As a result, there’s nothing known that makes a regular meal of a darkweaver.

Despite the weaver’s alien appearance, it’s a subtle creature that enjoys its mastery of suggestion and illusion. Nothing pleases a darkweaver more than tricking its foes into placing themselves at its mercy.