Shadowy Form.

While the darkweaver is in dim light or darkness, attack rolls against it are made with disadvantage unless the darkweaver has the incapacitated condition.

Spider Climb.

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

Sunlight Hypersensitivity.

The darkweaver takes 10 radiant damage when it starts its turn in sunlight. While in sunlight, it has disadvantage on attack rolls and ability checks.

Actions

Multiattack.

The darkweaver makes two Shadow Web attacks and one Bite attack. It can use Reel after any of these attacks.

Bite.

Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 13 (3d6 + 3) piercing damage plus 17 (5d6) necrotic damage, and if the target is a creature, the target's hit point maximum is reduced by an amount equal to the necrotic damage taken. This reduction lasts until the target finishes a long rest. The target dies if its hit point maximum is reduced to 0.

Shadow Web.

Ranged Weapon Attack: +7 to hit, reach 120 ft., one creature. Hit: 16 (3d10) necrotic damage, and the target has the grappled condition (escape DC 15). The shadow web can be attacked and destroyed (AC 16; 20 hit points; vulnerability to radiant damage; immunity to bludgeoning, necrotic, poison, and psychic damage). The darkweaver can grapple up to six creatures at a time using its shadow web.

Reel.

The darkweaver pulls each creature it has grappled up to 60 feet toward itself.

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