Magic Resistance. The Abyssal Draconis has advantage on saving throws against spells and other magical effects.

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

Regeneration. The Abyssal Draconis regains 20 hit points at the start of its turn if it has at least 1 hit point.

Cursed Aura. At the start of each of the Abyssal Draconis's turns, each creature within 30 feet of it takes 10 necrotic damage. This damage ignores resistance and immunity.

Multiattack. The Abyssal Draconis makes three attacks: one with its bite, one with its claw, and one with its tail.

Bite. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 22 (3d8 + 8) piercing damage plus 10 (3d6) necrotic damage.

Claw. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 18 (2d8 + 8) slashing damage plus 10 (3d6) fire damage.

Tail. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 20 (3d8 + 8) bludgeoning damage.

Breath Weapon (Recharge 5-6). The Abyssal Draconis exhales a blast of destructive energy in a 60-foot cone. Each creature in that area must make a DC 21 Dexterity saving throw, taking 66 (12d10) necrotic damage on a failed save, or half as much damage on a successful one.

Molten Claws. The Abyssal Draconis envelops its claws in molten energy, increasing the damage of its next claw attack by an additional 10 (3d6) fire damage.

Flaming Reprisal. When the Abyssal Draconis is hit by a melee attack, it can use its reaction to release a burst of flames. The attacker must make a DC 21 Dexterity saving throw, taking 21 (6d6) fire damage on a failed save, or half as much damage on a successful one.

Tail Swipe. When a creature moves within 10 feet of the Abyssal Draconis, it can make a tail attack against that creature as a reaction.

The Abyssal Draconis 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 Abyssal Draconis regains spent legendary actions at the start of its turn.

Attack. The Abyssal Draconis makes one claw or tail attack.
Teleport. The Abyssal Draconis magically teleports, along with any equipment it is wearing or carrying, up to 60 feet to an unoccupied space it can see.
Wing Attack (Costs 2 Actions). The Abyssal Draconis beats its wings. Each creature within 15 feet of the Abyssal Draconis must succeed on a DC 21 Dexterity saving throw or take 15 (2d6 + 8) bludgeoning damage and be knocked prone. The Abyssal Draconis can then fly up to half its flying speed.