Vlintesx, the Green Plague

Amphibious. The dragon can breathe air and water.

Legendary Resistance (3/Day). If Vlintesx fails a saving throw, he can choose to succeed instead.

Poisonous Aura. Creatures near Vlintesx must succeed on a Constitution saving throw (DC 19) or take 77 (22d6) poison damage. (it might look buggy, but it works)

Multiattack. Vlintesx can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 19 (2d10 + 8) piercing damage plus 10 (3d6) poison damage.

Claw. Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 22 (4d6 + 8) slashing damage.

Tail. Melee Weapon Attack: +15 to hit, reach 20 ft., one target. Hit: 17 (2d8 + 8) bludgeoning damage.

Frightful Presence. Each creature of Vlintesx's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 19 Wisdom saving throw or become frightened and poisoned 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 Vlintesx's Frightful Presence for the next 24 hours.

Poison Breath (Recharge 5–6). Vlintesx exhales poisonous gas in a 90-­-foot cone. Each creature in that area must make a DC 22 Constitution saving throw, taking 77 (22d6) poison damage on a failed save, or half as much damage on a successful one.

Vlintesx 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. Vlintesx regains spent legendary actions at the start of his turn.

Detect. Vlintesx makes a Wisdom (Perception) check.

Tail Attack. Vlintesx makes a tail attack.

Wing Attack (Costs 2 Actions). Vlintesx beats his wings. Each creature within 15 feet of him must succeed on a DC 23 Dexterity saving throw or take 15 (2d6 + 8) bludgeoning damage and be knocked prone. Vlintesx can then fly up to half its flying speed.