Quavilithku Spyder-Fiend

Large fiend (demon), typically chaotic evil

Armor Class

19 (natural armor)

Hit Points

256 (27d10 + 108)

Speed

40 ft., climb 40 ft.

Saves

wis +8, con +10, dex +9

Skills

stealth +9, investigation +9, perception +8

Damage Resistances

cold, fire, lightning

Damage Immunities

acid, poison

Condition Immunities

poisoned

Senses

truesight 60 ft.

Languages

Abyssal, Common, telepathy 120 ft.

Challenge

17

Proficiency Bonus

+6

Magic Resistance

The quavilithku has advantage on saving throws against spells and other magical effects.

Spider Climb

The quavilithku can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Web Sense

When in contact with a web, the quavilithku knows the exact location of any other creature in contact with the same web.

Web Walker

The quavilithku ignores movement restrictions caused by webbing.

Actions

Multiattack

The quavilithku makes two Bite attacks.

Bite

Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 15 (2d10 + 4) piercing damage plus 17 (5d6) poison damage. If the target is a creature, it must succeed on a DC 18 Constitution saving throw or have the poisoned condition for 1 minute. While poisoned in this way, a creature can't regain hit points. A poisoned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Dissolving Web (Recharge 5-6)

The quavilithku expels acid-drenched webs in a 90-foot cone. Each creature in that area must make a DC 18 Constitution saving throw, taking 44 (8d10) acid damage on a failed save or half as much damage on a successful one. Nonmagical objects in the area that aren't being worn or carried take 44 (8d10) acid damage.

Assess Weakness (Bonus Action)

The quavilithku sizes up a creature it can see within 40 feet of itself. Until the start of the quavilithku's next turn, it has advantage on attack rolls against the creature.