Riful, the Goddess's Blight

Spider Climb. Riful can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Web Sense. While in contact with a web, the Riful knows the exact location of any other creature in contact with the same web.

Web Walker. Riful ignores movement restrictions caused by webbing.

Sunlight Sensitivity. While in sunlight, the wraith has disadvantage on attack rolls and on Wisdom (Perception) checks that rely on sight.

Legendary Resistance (4/Day). If Riful fails a saving throw, she can choose to succeed instead.

Boon of Lady Doom (Recharges after a Short or Long Rest). If Riful would be reduced to 0 hit points, its current hit point total instead resets to 350 hit points, and it recharges its Caustic Spittle. Additionally, Riful can now use the options in the "Mythic Actions" section for 1 hour.

Multiattack. Riful takes three attacks: one with her fangs, and two with her legs.

Envenomate. Melee Weapon Attack: +10 to hit, reach 5 ft., one creature. Hit: 30 (5d8 + 7) piercing damage, and the target must make a DC 18 Constitution saving throw, taking 9 (2d8) poison damage on a failed save, or half as much damage on a successful one.

Spear. Melee Weapon Attack: +10 to hit, reach 5 ft., one creature. Hit: 25 (5d6 + 7) piercing damage.

Caustic Spittle (Recharge 5–6). Ranged Weapon Attack: +7 to hit, range 30/60 ft., one creature. Hit: The target is stunned by caustic spittle until the end of its second turn after being affected. As an action, the stunned target can make a DC 18 Strength check at the beginning of its turns, shaking the stunning effect on a success. 

Riful can take three 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. Riful regains spent legendary actions at the start of her turn.

Regeneration (Costs 2 Actions). Riful regains 75 hit points. 

Web. Ranged Weapon Attack: +5 to hit, range 30/60 ft., one creature. Hit: The target is restrained by webbing. As an action, the restrained target can make a DC 16 Strength check, bursting the webbing on a success. The webbing can also be attacked and destroyed (AC 15; HP 25; vulnerability to fire damage; immunity to bludgeoning, poison, and psychic damage).

Flail (Costs 2 Actions). Riful lashes out with her legs. Each creature within 15 feet of the spider must succeed on a DC 20 Dexterity saving throw or take 17 (2d6 + 10) bludgeoning damage and be knocked prone. She can then skitter away, up to half her movement speed.

If the Riful's Boon of Lady Doom trait has been activated in the last hour, it can use the options below as legendary actions.

Furious Bite (Costs 2 Actions). Riful makes one fang attack. If the attack hits a creature, the target must succeed on a DC 22 Wisdom saving throw or become frightened of her until the end of the target’s next turn.

Necrobolt (Costs 3 Actions). Riful conjures four enormous bolts of necrotic energy that plummet to the ground at four different points she can see within 150 feet of her and then disappear. Each creature in a 20-foot-radius, 100-foot-high cylinder centered on each point must succeed on a DC 25 Dexterity saving throw or take 24 (7d6) necrotic damage. A creature in the area of more than one lance is affected only once.