Aglaraerose, The Shattered King's Consort

Amphibious. Aglaraerose can breathe air and water.

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

Verdant Scales. Aglaraerose's Verdant Scales make her immune to any harmful magic below level 4. She is also immune to nonmagical attacks. 

Kesh'Thul's Consort. As the Shattered King's Consort, her death is impossible. When her hp is reduced to 0, return her to her skull form. Kesh'Thul is immediately notified when his consort is killed.

Aura of Purity and Desecration. Aglaraerose has an aura 60 feet around her that allows her to turn any poison or necrotic damage into healing or vice versa.

Multiattack. Aglaraerose can use her Frightful Presence. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 25 (3d10 + 8) piercing damage plus 18 (5d6) poison damage.

Claw. Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 22 (4d6 + 8) slashing damage.

Tail. Melee Weapon Attack: +15 to hit, reach 20 ft., one target. Hit: 17 (2d8 + 8) bludgeoning damage.

Frightful Presence. Each creature of Aglaraerose's choice that is within 160 feet of her and aware of her must succeed on a DC 23 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to Aglaraerose's Frightful Presence for the next 24 hours.

Venomous Breath (Recharge 6). Aglaraerose exhales venomous gas in a 120-­foot cone. Each creature in that area must make a DC 24 Constitution saving throw, taking 105(30d6) poison damage on a failed save, or half as much damage on a successful one. This damage treats resistance and immunity as one tier lower. (Resistance to neutral, Immunity to Resistance.)

Aglaraerose can take 3 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. Aglaraerose regains spent legendary actions at the start of its turn.

Detect. Aglaraerose makes a Wisdom (Perception) check.

Tail Attack. Aglaraerose makes a tail attack.

Wing Attack (Costs 2 Actions). Aglaraerose beats its wings. Each creature within 15 feet of Aglaraerose must succeed on a DC 23 Dexterity saving throw or take 20 (3d6 + 8) bludgeoning damage and be knocked prone. Aglaraerose can then fly up to half its flying speed.

Polymorph. Aglaraerose transforms into a humanoid race of her choice, preferring Lizardfolk or Dragonborn.