Shadowspider Swarm

Large swarm of Tiny monstrosities, neutral evil

Armor Class 15 (natural armor)
Hit Points 102 (12d10 + 36)
Speed 30 ft., climb 30 ft.

14 (+2) 18 (+4) 16 (+3) 8 (-1) 10 (+0) 5 (-3)

Damage Resistances bludgeoning, piercing, slashing
Damage Immunities cold, necrotic
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Senses darkvision 120 ft., passive Perception 10
Challenge 5 (1,800 XP)
Proficiency Bonus +3


  • Darkwalkers. While in darkness, the shadowspider swarm is invisible.
  • Sense Life. The shadowspider swarm can pinpoint the location of a warm, living creature within 30 feet.
  • Swarm. The shadowspider swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Tiny shadowspider. The swarm can’t regain hit points or gain temporary hit points.
  • Wasting Wave. A creature that enters the swarm’s space for the first time on a turn or ends its turn in the swarm’s space must succeed on a DC 14 Constitution saving throw or gain one level of shadow corruption.


  • Shadow Bites. Melee Weapon Attack: +7 to hit, reach 0 ft., one creature in the swarm’s space. Hit: 14 (4d6) piercing damage, or 7 (2d6) piercing damage if the swarm has half of its hit points or fewer. The target must make a DC 14 Constitution saving throw, taking 9 (2d8) necrotic damage and 9 (2d8) cold damage on a failed save or half as much damage on a successful one.


This mass of fist-sized black spiders flows like a creeping mist. While they move like a shadow across the ground, they do not cast one themselves.

Born of Darkness. Shadowspiders are not alive in the traditional sense. A shadowspider swarm is a creeping mass of spiders formed out of the primordial darkness of the Shadow Realm itself. They are born in the oldest and darkest regions of the Shadow Realm, often in areas where the planar barriers have grown thin. Unable to survive outside of its swarm, a shadowspider separated from its swarm evaporates in a greasy swirl of black smoke.

Affinity with Undeath. While shadowspider swarms form in places where two planes are close, they are particularly common in regions where the Shadow Realm is coterminous with the Plane of Undeath. Because of this, shadowspider swarms are often found alongside the undead that sometimes spill forth in these regions.

Insatiable. Shadowspider swarms are always hungry, especially for the warmth of mortals. When a shadowspider swarm senses the warmth of a living creature, it immediately moves to consume the creature.

Section 15: Copyright Notice

Book of Ebon Tides © 2022 Open Design LLC; Authors: Wolfgang Baur, Celeste Conowitch.

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