Adult Black Dragon

Huge dragon · CR 14

Armor Class 19
Hit Points 195 (17d12+85)
Speed fly 80 ft., swim 40 ft., 40 ft.
STR 23 +6
DEX 14 +2
CON 21 +5
INT 14 +2
WIS 13 +1
CHA 17 +3
Saving Throws CHA+8, CON+10, DEX+7, WIS+6
Skills perception +11, stealth +7
Damage Immunities acid
Senses blindsight60 ft., darkvision120 ft. , passive Perception 21
Languages Common, Draconic

Traits

Amphibious.
The dragon can breathe air and water.
Legendary Resistance (3/Day).
If the dragon fails a saving throw, it can choose to succeed instead.

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/Ranged Weapon Attack: +11 to hit.
Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) piercing damage plus 4 (1d8) acid damage.
Claw. Melee/Ranged Weapon Attack: +11 to hit.
Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) slashing damage.
Tail. Melee/Ranged Weapon Attack: +11 to hit.
Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 15 (2d8 + 6) bludgeoning damage.
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 16 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.
Acid Breath (Recharge 5-6). Melee/Ranged Weapon Attack: +0 to hit.
The dragon exhales acid in a 60-foot line that is 5 feet wide. Each creature in that line must make a DC 18 Dexterity saving throw, taking 54 (12d8) acid damage on a failed save, or half as much damage on a successful one.

Legendary Actions

The Adult Black Dragon 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 creature regains spent legendary actions at the start of its turn.

Detect.
The dragon makes a Wisdom (Perception) check.
Tail Attack.
The dragon makes a tail attack.
Wing Attack (Costs 2 Actions) (Costs 2 Actions).
The dragon beats its wings. Each creature within 10 ft. of the dragon must succeed on a DC 19 Dexterity saving throw or take 13 (2d6 + 6) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.