Anoth-Zuul, the Dragon Queen

Innate Spellcasting. Anoth-Zuul can cast the following spells without need for components. Her spellcasting modifier is Wisdom (+13, DC 21).
At will: chill touch (17th level)
1/Long rest: animate dead (5th level)
2/Long rest: finger of death, vampiric touch (8th level)

Aura of Exultation. The cultists and undead who worship Anoth-Zuul are empowered by her presence. Any cultist or undead that starts their turn within 60 feet of Anoth-Zuul gains 10 temporary hit points at the start of their turn and while in this aura makes all attacks with advantage.

Legendary Resistance (3/Long rest). If Anoth-Zuul fails a saving throw, she can choose to succeed instead.

Magic Resistance. Anoth-Zuul has an advantage on saving throws against spells and other magical effects.

True Form. If Anoth-Zuul is in her dragon form, on every turn, the shapeshifting abilities around her need a DC 15 to maintain the transformation. If it fails, the creature returns to its original form.

Multiattack. Anoth-Zuul can use her Frightful Presence. She then makes three attacks: one with her bite and two with her claws.

Breath of Harm (Recharge 5-6) : Anoth-Zuul unleashes a torrent of plague-bringing breath in a 60-foot cone. Each Creature in the cone must make a Con Save (DC 17). On a failed save, take 49 (14d6) necrotic damage or half as much on a success. If it fails, the creature can't be reduced to fewer than 1 Hit point.

Rotten Bite: Melee Weapon attack, +10 to hit, reach 15ft, one target. Hit 19 (2d10 + 8) piercing damage plus 9 (2d8) necrotic damage. If the target is a creature, it must succeed on a DC 14 Constitution saving throw or be cursed with mummy rot. The cursed target can't regain hit points and its hit point maximum decreases by 10 (3d6) for every 24 hours that elapse. While under the curse, if the target's hit becomes 0 or lower, and it fails to succeed the death saves, the target dies and turns into dust.

Rotten Claw: Melee Weapon attack, +11 to hit, reach 10 ft, one target. Hit 16 (2d6 + 9)  necrotic damage. 

Tail: Melee Weapon Attack +10 to hit, reach 20ft, one target. Hit 15 (2d8 + 6) bludgeoning damage.

Frightful Presence: Any creature within 120 feet of Anoth-Zuul and aware of her presence must succeed on a DC 19 Wisdom saving throw or become frightened for one 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, the creature is immune to Anoth-Zuul's Frightful Presence for the next 24 hours

Healing (Recharge 5-6) : Anoth-Zuul can heal 40 (5d12+10) hit points.

Anoth-Zuul 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. Anoth-Zuul regains spend legendary actions at the start of her turn.

Detect: Anoth-Zuul makes a Wisdom (Perception) Check.

Glare of the Ancients: Anoth-Zuul targets one creature she can see within 60ft. If the target can see Anoth-Zuul, it must succeed on a DC 18 Wisdom saving throw against this magic or become stunned until the end of Anoth-Zuul's next turn. If the target fails the saving throw by 5 or more, it is also paralyzed for the same duration. A target that succeeds on the saving throw is immune to this glare as well as the Dreadful Glare of all mummies and mummy lords for the next 24 hours.

Tail Attack: Anoth-Zuul makes a tail attack

Wingstorm (Costs 2 Actions): Anoth-Zuul beats her massive wings as blinding dust and sand swirls magically around her. Each creature within 15 feet of Anoth-Zuul must succeed on a DC 16 Con Save or be blinded until the end of the creature's next turn. Anoth-Zuul can then move up to her fly speed without provoking opportunity attacks.