Flyby. The dragon doesn't provoke an opportunity attack when it flies out of an enemy's reach.

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

Actions

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

Bite. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 18 (2d10 + 7) piercing damage.

Tail. Melee Weapon Attack: +14 to hit, reach 20 ft., one target. Hit: 25 (4d8 + 7) bludgeoning damage.

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 19 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.

Thunder Breath (Recharge 5-6). The dragon exhales a sudden, powerful burst of air in a 90-foot cone. Each creature in that area must make a DC 21 Constitution saving throw. On a failed save, a creature takes 91 (14d12) thunder damage and is pushed 20 feet away from the dragon. On a successful save, the creature takes half as much damage and isn’t pushed.

Legendary Actions

The dragon 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.