Heated Aura. At the start of each of the dragon's turns, or whenever its hit by a melee attack from a hostile creature, it deals 2 (1d4) fire damage to each creature within 15 ft of it. 

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: +9 to hit, reach 10 ft., one target. Hit: 16 (2d10 + 5) piercing damage plus 4 (1d8) fire damage.

Claw. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) slashing damage.

Tail. Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit: 14 (2d8 + 5) bludgeoning damage.

Fireball. Ranged Weapon Attack: +4 to hit, range 20/60 ft., one target. Hit: 19 (3d12) fire damage.

Fire Breath (Recharge 5-6). The dragon exhales an burst of flame in a 55-foot cone or 60-foot, 10-feet wide line. Each creature in that area must make a DC 18 Constitution saving throw, taking 49 (11d8) fire damage on a failed save, or half as much damage on a successful one.

Death Gaze (1/Day). The dragon makes a Fireball attack on a target within range, which has advantage if the target is vulnerable to fire or bludgeoning damage. On a hit, the target takes no damage but must succeed on a DC 17 Constitution saving throw or, if it has 70 hit points or less, drop to 0 hit points immediately. 

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.

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 20 Dexterity saving throw or take 15 (2d6 + 8) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.