Ancient Bronze Dragon

The ancient bronze dragon can breathe air and water.

4/day (5/day in lair). If the ancient bronze dragon fails a saving throw, it can choose to succeed instead.

The ancient bronze dragon makes three Rend. It can replace one attack with a use of (A) Repulsion Breath or (B) Spellcasting to cast Guiding Bolt (level 2 version).

Melee Weapon Attack: +16 to hit, reach 15 ft.. Hit: 18 (2d8 + 9) slashing plus 9 (2d8) lightning damage.

Strength Saving Throw: DC 23, each creature in a 30-foot Cone.
Failure: The target is pushed up to 60 feet straight away from the ancient bronze dragon and has the Prone condition.

Recharge 5–6. Dexterity Saving Throw: DC 23, each creature in a 120-foot-long, 10-foot-wide Line.
Failure: 82 (15d10) lightning damage.
Success: Half damage.

1 use per day. The ancient bronze dragon casts one of the following spells, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 22, +14 to hit with spell attacks):
At Will: Detect Magic, Guiding Bolt (level 2 version), Shapechange (Beast or Humanoid form only, no Temporary Hit Points gained from the spell, and no Concentration or Temporary Hit Points required to maintain the spell), Speak with Animals, Thaumaturgy
1/Day Each: Detect Thoughts, Control Water, Scrying, Water Breathing

The ancient bronze dragon uses Spellcasting to cast Guiding Bolt (level 2 version).

The ancient bronze dragon moves up to half its Speed, and it makes one Rend attack.

Constitution Saving Throw: DC 22, each creature in a 20-foot-radius Sphere centered on a point the ancient bronze dragon can see within 90 feet.
Failure: 13 (3d8) thunder damage, and the target has the Deafened condition until the end of its next turn.