Armor Class 18
Hit Points 212 (17d12 + 102)
Speed 40 ft., fly 80 ft., swim 40 ft.
Saving Throws DEX +5, WIS +7
Skills Insight +7, Perception +12, Stealth +5
Damage Immunities lightning
Senses Blindsight 60 ft., Darkvision 120 ft., passive Perception 22
Languages Common, Draconic
Challenge 15
Amphibious. The dragon can breathe air and water.
Legendary Resistance (3/Day, or 4/Day in Lair). If the dragon fails a saving throw, it can choose to succeed instead.
Multiattack. The dragon makes three Rend attacks. It can replace one attack with a use of (A) Repulsion Breath or (B) Spellcasting to cast Guiding Bolt (level 2 version).
Rend. m +12, reach 10 ft. Hit: 16 (2d8 + 7) Slashing damage plus 5 (1d10) Lightning damage.
Lightning Breath (Recharge 5–6). dex DC 19, each creature in a 90-foot-long, 5-foot-wide Line. 55 (10d10) Lightning damage. Half damage.
Repulsion Breath. str DC 19, each creature in a 30-foot Cone. The target is pushed up to 60 feet straight away from the dragon and has the Prone condition.
Guiding Light. The dragon uses Spellcasting to cast Guiding Bolt (level 2 version).
Pounce. The dragon moves up to half its Speed, and it makes one Rend attack.
Thunderclap. con DC 17, each creature in a 20-foot-radius Sphere centered on a point the dragon can see within 90 feet. 10 (3d6) Thunder damage, and the target has the Deafened condition until the end of its next turn.
Monster Manual (2024), p. 59