Armor Class 18
Hit Points 178 (17d10 + 85)
Speed 40 ft., fly 80 ft., swim 40 ft.
Saving Throws DEX +6, WIS +5
Skills Insight +5, Perception +9, Persuasion +9, Stealth +6
Damage Immunities fire
Senses Blindsight 30 ft., Darkvision 120 ft., passive Perception 19
Languages Common, Draconic
Challenge 10
Amphibious. The dragon can breathe air and water.
Multiattack. The dragon makes three Rend attacks. It can replace one attack with a use of Weakening Breath.
Rend. m +10, reach 10 ft. Hit: 17 (2d10 + 6) Slashing damage.
Fire Breath (Recharge 5–6). dex DC 17, each creature in a 30-foot Cone. 55 (10d10) Fire damage. Half damage.
Weakening Breath. str DC 17, each creature that isn't currently affected by this breath in a 30-foot Cone. The target has Disadvantage on Strength-based D20 Tests and subtracts 3 (1d6) from its damage rolls. It repeats the save at the end of each of its turns, ending the effect on itself on a success. After 1 minute, it succeeds automatically.
Monster Manual (2024), p. 144