Ancient topaz dragon

Amphibious. The topaz dragon can breathe air and water. 

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

Innate Spellcasting (Psionics). The ancient topaz dragon's innate spellcasting ability is Intelligence. The ancient topaz dragon can innately cast the following spells, requiring no material components:

At will: control weather, control winds, feather fall, fog cloud

Multi attack. The ancient topaz dragon uses its frightful presence, a bite attack and two claw attacks. 

Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., 1 target. Hit: 13 (2d8 + 5) piercing damage. 

Claw. Melee Weapon Attack: +10 to hit, reach 5 ft., 1 target. Hit: 9 (2d4 + 5) slashing damage. 

Tail. Melee Weapon Attack: +10 to hit, reach 15 ft., 1 target. Hit: 11 (2d6 + 5) 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 19 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.

Dehydration breath (Recharges on 5/6). The topaz dragon exhales a blast of a watery substance in a 90ft cone. Each creature within range must make a DC 16 Constitution saving throw or the creature gains two levels of exhaustion. This breath also can also destroy 16 cubic feet of water. 

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

Detect (Costs 1 Action). The dragon makes a Wisdom (Perception) check.

Tail Attack (Costs 1 Action). The dragon makes a tail attack.

Teleport (Costs 2 Actions). The topaz dragon teleports up to 100ft to a place that they can see that isn't currently occupied.