Ancient Brass Dragon is a Gargantuan dragon with chaotic good alignment and Challenge Rating 20 in the 2024 SRD. This stat block includes AC 20, 332 hit points, speeds, traits, and actions.
Multiattack - The dragon makes three Rend attacks. It can replace one attack with a use of (A) Sleep Breath or (B) Spellcasting to cast Scorching Ray (level 3 version).
Rend - Melee Attack Roll: +14, reach 15 ft. Hit: 19 (2d10 + 8) Slashing damage plus 7 (2d6) Fire damage.
Fire Breath - Dexterity Saving Throw: DC 21, each creature in a 90-foot-long, 5-footwide Line. Failure: 58 (13d8) Fire damage. Success: Half damage.
Sleep Breath - Constitution Saving Throw: DC 21, each creature in a 90-foot Cone. Failure: The target has the Incapacitated condition until the end of its next turn, at which point it repeats the save. Second Failure: The target has the Unconscious condition for 10 minutes. This effect ends for the target if it takes damage or a creature within 5 feet of it takes an action to wake it.
Spellcasting - The dragon casts one of the following spells, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 20):