Endelyn Moongrave

Endelyn is immune to any effect that would age her, and she can't die from old age.

Endelyn can be killed only if she is reduced to 0 hit points during a solar eclipse or while she is within 60 feet of a symbolic representation of one. Otherwise, Endelyn disappears in a cloud of inky smoke when she drops to 0 hit points, along with anything she was wearing or carrying, and reappears 24 hours later in the same location or the nearest unoccupied space.

Endelyn can't be surprised.

Endelyn casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability (spell save DC 14):

At will: detect magic, mage hand

1/day: plane shift (self only)

2/day each: augury, polymorph

Endelyn makes two Puppeteer's Lash attacks

Melee or Ranged Spell Attack: +6 to hit, reach 5 ft. or range 60 ft., one creature. Hit: 17 (4d6 + 3) psychic damage, and if the target is Large or smaller, Endelyn telekinetically moves it up to 10 feet in any direction horizontally.