Alluring Aura. Any creature hostile to Glasya that starts their turn within 10 feet of must make a DC 24 charisma saving throw, unless she is incapacitated. If failure, the creature is charmed until the start of that creature's next turn.  If the creature takes damage, the creature is no longer charmed by Glasya.  If any creature is successful against this saving throw, they are immune to Glasya's Alluring Aura for the next 24 hours.

Innate Spellcasting. Glasya's spellcasting ability is charisma, (spell save DC 26, +16 to hit), Glasya can cast the following spells, requiring no material components:

At will:  alter self (can become a medium creature when changing her appearance), charm person, fast friends, fireball, incite greed, distort value, suggestion

3 day/each: counterspell (at 5th level), dispel magic, dominate monster, geas, mirror image, mislead, raise dead, wall of fire

1 day/each: imprisonment, feeblemind, reverse gravity

Magic Resistance. Glasya has advantage on saving throws against spells and other magical effects.

Hellish Weapons. Glasya's weapon attacks are magical and deal an extra 18 (4d8) poison damage on a hit (included in the attacks).

Regeneration. Glasya regains 20 hit points at the start of her turn. If she takes radiant damage, this trait does not function at the start of her turn.  Glasya dies only at the start of her turn with 0 hit points and doesn't regenerate.

Legendary Resistance (3/Day). If Glasya fails a saving throw, she can choose to succeed instead.

Multiattack. Glasya makes three melee attacks: two with its scourge and one with its tail. It can use Hurl Flame in place of any melee attack.

Scourge. Melee Weapon Attack: +16 to hit, reach 15 ft range, one target, hit 24 (3d8+8) slashing damage, plus 18 (4d8) poison damage on a hit.

Tail. Melee Weapon Attack: +16 to hit,, reach 10 ft., one target. Hit: 24 (3d10+8) piercing damage. If the target is a creature, it must make a DC 24 constitution saving throw or be poisoned for one hour.

Sickening Embrace (Recharge 5-6). Melee Weapon Attack: +16 to hit, reach 10 ft., one target. Hit 44 (8d10) psychic damage, and the target is incapacitated for one minute.  While incapacitated in this way, the target is blinded, deafened, and knocked prone.  The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Teleport. Glaysa magically teleports along with any of her equipment she is wearing or anything she is carrying, up to 120 feet to an unoccupied space she can see.

Glasya had three legendary actions per turn. Choosing from the items below. One legendary option can be used at a time and only at the end of another creature's turn. Glasya regains all of her legendary actions at the beginning of her turn.

Summon Erinyes (Cost 3 actions). Glasya magically summons an erinyes with a Rope of Entanglement. The erinyes appears in an unoccupied space within 60 feet of Glasya, acts as Glasya's ally, and can summon other devils if it has such power.  The erinyes remains as long as Glasya is alive or until she dismisses it as an action.

Scourge Attack (Cost 1 action). Glasya can make a melee attack with her scourge.

Teleport (Cost 1 action). Glasya can use her teleport action.