Huge dragon, lawful good

Armor Class 19 (natural armor)

Hit Points 212 (17d12+102)

Speed 40 ft., fly 80 ft., swim 40 ft.

STR DEX CON INT WIS CHA
25 (+7) 10 (0) 23 (+6) 16 (+3) 15 (+2) 19 (+4)

Saving Throws Dex +5, Con +11, Wis +7, Cha +9

Skills Insight +7, Perception +12, Stealth +5

Damage Immunities lightning

Senses blindsight 60 ft., darkvision 120 ft.

Languages Common, Draconic

Challenge 15 (13,000 XP)

Amphibious. The dragon can breathe air and water.

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 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 (Recharge 5-6). 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.

Legendary Actions

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.

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 10 ft. of the dragon must succeed on a DC 20 Dexterity saving throw or take 14 (2d6 + 7) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.