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: +12 to hit, reach 10 ft., one target. Hit: 18 (2d10 + 7) piercing damage.
Claw - Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 14 (2d6 + 7) slashing damage.
Tail - Melee Weapon Attack: +12 to hit, reach 15 ft., one target. Hit: 16 (2d8 + 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 17 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.
Breath Weapons - The dragon uses one of the following breath weapons. Lightning Breath. The dragon exhales lightning in a 90-foot line that is 5 feet wide. Each creature in that line must make a DC 19 Dexterity saving throw, taking 66 (12d10) lightning damage on a failed save, or half as much damage on a successful one. Repulsion Breath. The dragon exhales repulsion energy in a 30-foot cone. Each creature in that area must succeed on a DC 19 Strength saving throw. On a failed save, the creature is pushed 60 feet away from the dragon.
The Adult Bronze 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 Adult Bronze Dragon regains spent legendary actions at the start of its turn.