Black Death Shadow Dragon

Aura of Death. Creatures that first enters or starts its turn within 20ft. of the dragon cannot regain hitpoints until the start of its next turn.

Change Shape. The dragon magically polymorphs into a humanoid or beast that has a challenge rating no higher than its own, or back into its true form. It reverts to its true form if it dies. Any equipment it is wearing or carrying is absorbed or borne by the new form (the dragon's choice).

In a new form, the dragon retains its alignment, hit points, Hit Dice, ability to speak, proficiencies, Legendary Resistance, lair actions, and Intelligence, Wisdom, and Charisma scores, as well as this action. Its statistics and capabilities are otherwise replaced by those of the new form, except any class features or legendary actions of that form.

Death Eater. When the dragon takes necrotic damage, it regains a number of hitpoints equal to the damage dealt.

Innate Spellcasting (3/Day). The dragon can innately cast divine word (spell save DC 26). Her spellcasting ability is Charisma.

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

Regeneration. The dragon regains 20 hit points at the start of their turn.

Unusual Nature. The dragon doesn’t require air, food, drink, or sleep.

Multiattack. The dragon can make four attacks, one with its bite, two with its claws, and one with its tail.

Bite. Melee Weapon Attack: +17 to hit, reach 15 ft., one target. Hit: 21 (2d10 + 10) piercing damage.

Claw. Weapon Attack: + 19 to hit, reach 15 ft., one target. Hit: 24 (4d6 + 10) slashing damage.

Tail. Melee Weapon Attack: + 19 to hit, reach 25 ft., one target. Hit: 28 (4d8 + 10) piercing damage

Breath Weapons (Recharge 5–6). The dragon uses one of the following breath weapons.

Cataclysmic Breath (Recharge 2). The dragon exhales a wave of ghostly purple flames in a 60-foot cone. Each creature in that area must make a DC 18 Dexterity saving throw, taking 45 (10d8) necrotic damage on a failed save, or half as much damage on a successful one. A creature dies if the breath reduces it to 0 hit points. Additionally, any Medium or smaller Humanoid killed by the breath’s damage, as well as every corpse of such a creature within the cone, becomes a zombie (see the Monster Manual) under the dragon’s control. The zombie acts on the dragon’s initiative but immediately after the dragon’s turn. Absent any other command, the zombie tries to kill any non-Undead creature it encounters.

Fire Breath. The dragon exhales fire in a 90-foot cone. Each creature in that area must make a DC 24 Dexterity saving throw, taking 71 (13d10) fire damage on a failed save, or half as much damage on a successful one.

Weakening Breath. The dragon exhales gas in a 90-foot cone. Each creature in that area must succeed on a DC 24 Strength saving throw or have disadvantage on Strength-based attack rolls, Strength checks, and Strength saving throws 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..

The dragon can take 3 legendary actions, choosing from the options below. Only one legendary action 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.

Cataclysmic Rush (Costs 2 Actions). The dragon moves up to half its flying speed without provoking opportunity attacks, carrying with it any creatures it is grappling. During this move, if it enters the space of a Medium or smaller creature, that creature takes 4 (1d8) necrotic damage. A creature can take this damage only once per turn.

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.