Andranta; Eater of Worlds

Legendary Resistance (5/Day). If the dragon fails a saving throw, it can choose to succeed instead.

Keen Smell. Andranta has advantage on all Wisdom saving throws that involve smell.

Curse Mark. When struck with a melee weapon attack, Andranta gnashes at its target as curse magic seeps into their mind, driving them into madness. Each turn the marked foe must make a Constitution 19 saving throw or take (4d8 + 6) curse damage. If the target succeeds they take have as much and the curse subsides. Additionally, if Andranta attacks a cursed foe they take an additional (4d8 +6) curse damage with each hit.

Unknowing Aura. If Andranta hits a creature with a bite attack, they lose all proficiencies they have for 10 minutes.

Draining Presence. Any creature in a 5 foot radius around Andranta is drained of 2d6 hit points on their turn. The health lost from the drainage is given to Andranta as temporary hit points.

Master of the Arcane. Andranta has advantage on saving throws against spells and other magical effects.

True Sight. A creature with true sight can, out to a specific range, see in normal and magical darkness, see invisible creatures and objects, automatically detect visual illusions and succeed on saving throws against them, and perceives the original form of a shapechanger or a creature that is transformed by magic. Furthermore, the creature can see into the Ethereal Plane.

Cursive Aura. When a hostile character begins its turn within 30 feet of the dragon, they have to make a Constitution 19 saving throw or suffer 1 point of Exhaustion.

Death's Kiss (3/Day) If Andranta falls below 150 hit points, it can use its reaction to sacrifice a willing creature on the field, bringing it to 0 hit points. Andranta then gains the remaining hit points that monster had before being sacrificed. 

Death's Gambit. (1/Day) If Andranta falls below 100 hit points, curse magic begins to spoon its body as it enters a stage of pure terror. This allows Andranta to permanently gains the effects of the haste spell until it falls to 0 hit points, or is healed above 100 again. This ability also triggers the Frightful Presence action.

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

Bite. Melee Weapon Attack: +17 to hit, reach 15 ft., one target. Hit: 21 (2d10 + 10) piercing damage plus 14 (4d6) fire damage. If hit this attack triggers Andranta's curse mark

Claw. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 17 (2d6 + 10) slashing damage. If hit this attack triggers Andranta's curse mark

Tail. Melee Weapon Attack: +17 to hit, reach 20 ft., one target. Hit: 19 (2d8 + 10) bludgeoning damage. If hit this attack triggers Andranta's curse mark

Frightful Presence. Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 21 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 the dragon's Frightful Presence for the next 24 hours.

Cursed Breath (Recharge 5–6). Cursed lightning crackles from the dragon's maw, exhaling crimson lightning in a 90-foot cone. Each creature in that area must make a DC 24 Dexterity saving throw, taking 91 (26d6) curse damage on a failed save, or half as much damage on a successful one.

Cursed Shield. Cursed Sludge encases Andranta's scales giving it a +2 Bonus to AC until its next turn. 

Puppet Master. Andranta can command a willing creature under its control as a bonus action. This includes being able to move the creature equal to half its movement speed, and making one action with that creature. While under Andrantas control, it doesn't gain any benefits from proficiencies.

Breath Preparation. As a bonus action Andranta can re roll to recharge its breath weapon if the action is not yet charged. This bonus action cannot be used if breath weapon was also used on the same turn.

Blight's Mark. As a bonus action, Andranta can cause a cursed foe to feel immense pain. Any marked creature Andranta can see must make a Constitution 19 saving throw or take (8d8 + 6) Necrotic damage. If the foe succeeds the save, it takes half damage diminishing the curse and making them unmarked.

Protective Stance. Andranta adds 5 to its AC against one melee attack that would hit it until it's next turn. To do so, Andranta must see the attacker.

Death's Shield. Andranta can reflect any ranged attack that would hit it back at its attacker. The attacker has to have rolled subsequent too or higher than its own AC to be struck by its own attack.

Andranta 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. The dragon regains spent legendary actions at the start of its turn.

Detect. The dragon makes a Wisdom (Perception) check.

Tail Attack. The dragon makes a tail attack.

Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 15 feet of the dragon must succeed on a DC 25 Dexterity saving throw or take 17 (2d6 + 10) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.

Cursive Thunder Andranta exhales lightning imbued with curse magic from it's mouth in a 150-foot line that is 15 feet wide. Each creature in that line must make a DC 19 Dexterity saving throw, taking 90 (20d8) lightning damage on a failed save, or half as much damage on a successful one.

Move. Andranta moves up to half its speed.