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: +18 to hit, reach 15 ft., one target. Hit: (2d10 + 10) piercing damage.   Claw. Melee Weapon Attack: +18 to hit, reach 10 ft., one target. Hit: (2d8 + 10) slashing damage. If the target is a Huge or smaller creature, it is grappled (escape DC 20 (10+Athletics)) and is restrained until this grapple ends. The greatwyrm can only have one creature grappled this way at a time.   Tail. Melee Weapon Attack: +18 to hit, reach 20 ft., one target. Hit: (2d10 + 10) bludgeoning damage. If the target is a creature, it must make a DC 26 (8 +Prof + Str) Strength saving throw or be knocked prone   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 20 (8 + Prof + Cha) 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.   Snaring Underbrush. The dragon creates a 40ft radius 20ft tall cylinder of awakened plant life, centered at a point on the ground somewhere within 150ft of it. This area is difficult terrain and lightly obscures. This area withers and disappears 1 hour after it was created. The dragon can use feature a number of times equal to half it's proficiency bonus (rounded up), it regains these uses when it finishes a short or long rest.   Lightning Breath (Recharge 5-6). The dragon exhales lightning in a 4000-foot line that is 10 feet wide. Each creature in that line must make a DC 21 (8 + Prof + Dex) Dexterity saving throw, taking 78 (12d12) lightning damage on a failed save, or half as much damage on a successful one.   Change Shape. The dragon magically polymorphs into a Humanoid or beast that has a Challenge rating no higher than its own, or back into its true form. It reverts to its true form if it dies. Any Equipment it is wearing or carrying is absorbed or borne by the new form (the dragon's choice). In a new form, the Dragon retains its Alignment, Hit Points, Hit Dice, ability to speak, Proficiencies, Legendary Resistance, lair Actions, and Intelligence, Wisdom, and Charisma scores, as well as this action. Its Statistics and capabilities are otherwise replaced by those of the new form, except any Class Features or legendary Actions of that form.

Legendary Actions

The greatwyrm 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 greatwyrm regains spent legendary actions at the start of their turn. Detect. The dragon makes a Wisdom (Perception) check.   Attack. The dragon makes a claw or tail attack.   Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 30 ft. of the dragon must succeed on a DC 26 (8 + Prof + Str) Dexterity saving throw or take 17 (2d6 + 10) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.   Growth Spurt (Costs 2 Actions). The dragon makes one area of plants created by it's Snaring Underbrush ability to surge with life, every creature within it's area must make a DC 26 (8 + Prof + Wis) Strength saving throw or be effected by this ability. The effect of this ability depends on what effects the creature is already subjected to through this ability.  

• If a creature that isn't currently grappled by this feature is affected, they are grappled, a grappled creature can as an action attempt to break free of this grapple making either an Athletics or Acrobatics check against a DC of 26 (8 + Prof + Wis), a a different creature within 5ft of the grappled creature may use an action to attempt to break the grappled creature free making an Athletics check against a DC of 26 (8 + Prof + Wis), in either case if the creature succeeds on the check the grappled creature is no longer grappled by this feature.
• If a creature that is already grappled by this feature is affected, they are restrained, if the creature stops being grappled by this feature they are no longer restrained.
• If a creature that is already restrained by this feature is affected, they are deafened, if the creature stops being grappled by this feature they are no longer deafened.
• If a creature that is already deafened by this feature is affected, they are blinded, if the creature stops being grappled by this feature they are no longer blinded.
• If a creature that is already blinded by this feature is affected, they are incapacitated, if the creature stops being grappled by this feature they are no longer incapacitated.
• If a creature that is already incapacitated by this feature is affected, they are stunned, if the creature stops being grappled by this feature they are no longer stunned.
• If a creature that is already stunned by this feature is affected, they are paralyzed, if the creature stops being grappled by this feature they are no longer paralyzed.
• If a creature that is already paralyzed by this feature is affected, they are made unconscious, if the creature stops being grappled by this feature they are no longer unconscious.

 

Mythic Actions

If the greatwyrm's Draconic Awakening trait has activated in the last hour, it can use the options below as legendary actions.   Bite. The greatwyrm makes a bite attack.   Shattering Roar (Costs 2 Actions). The greatwyrm unleashes a magical roar. Each creature in a 120-foot-radius sphere centered on the greatwyrm must succeed on a DC 20 (8 + Prof + Cha) Constitution saving throw or take 19 (3d12) thunder damage and be incapacitated until the end of its next turn.   Snaring Underbrush (Costs 3 Actions). The greatwyrm uses its Snaring Underbrush action.

Lair Actions

On initiative count 20 (losing initiative ties), the dragon takes a lair action to cause one of the following effects:  

• The dragon creates fog as though it had cast the fog cloud spell. The fog lasts until initiative count 20 on the next round.
• A thunderclap originates at a point the dragon can see within 120 feet of it. Each creature within a 20-foot radius centered on that point must make a DC 15 Constitution saving throw or take 5 (1d10) thunder damage and be deafened until the end of its next turn.

A bronze dragon lairs in coastal caves. It might salvage a wrecked ship, reconstruct it within the confines of its lair, and use it as a treasure vault or nest for its eggs.

Regional Effects

The region containing a legendary bronze dragon’s lair is warped by the dragon’s magic.  

• Once per day, the dragon can alter the weather in a 6-mile radius centered on its lair. The dragon doesn’t need to be outdoors; otherwise the effect is identical to the control weather spell.
• Underwater plants within 6 miles of the dragon’s lair take on dazzlingly brilliant hues.
• Within its lair, the dragon can set illusory sounds, such as soft music and strange echoes, so that they can be heard in various parts of the lair.

  If the dragon dies, changed weather reverts to normal, as described in the spell, and the other effects fade in 1d10 days.