Black Darakhon

Amphibious. The Darakhon can breathe air and water.

Legendary Resistance (3/day). If the Darakhon fails a saving throw, it can choose to succeed instead.

Multiattack. The Darakhon makes three attacks: two with its flail and one with its shield slam.

Flail. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 14 (2d8 + 5) bludgeoning damage. 

Shield Slam. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 12 (3d4 + 5) bludgeoning damage, and if the target is a creature, it must make a DC 17 Strength saving throw or be knocked prone.

Magnificent Presence. Each creature of the Darakhon's choice that is within 90 feet of the Darakhon and aware of it must succeed on a DC 15 saving throw or become frightened or charmed by it (the Darakhon's choice) for 1 minute. A creature can repeat the saving throw on 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 Darakhon's magnificent presence for the next 24 hours.

Acid Breath (Recharge 5-6). The Darakhon exhales acid in a 30-foot line that is 5 feet wide. Each creature in that line must make a DC 16 Dexterity saving throw, taking 22 (5d8) acid damage on a failed save, or half as much on a successful one.

The Darakhon 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 Darakhon regains spent legendary actions at the start of its turn.

Detect. The Darakhon makes a Wisdom (Perception) check.

Flail Attack. The Darakhon makes a flail attack.

Magnificent Presence. The Darakhon uses its Magnificent Presence trait.