Ashen Fliers. The dragon can breathe in any area that has an amount of air or smoke, regardless of how thin. It can hold its breath for up to ten minutes at a time.

Claret Scales. The dragon's flight speed is doubled while in smoke. Also while in smoke or soot-filled air, if the dragon moves at least 40 feet in a straight line before attacking, the attack deals an additional 11 (3d6) damage. The dragon cannot swim.

Fade Into Fog. The dragon can use its action to shapechange into a mass of semisolid smoke (or back to its dragon form). While in this form, the dragon has advantage on stealth checks and loses its walking and climbing speeds, but gains the hover property.

Spellcasting. The dragon is an innate spellcaster. Its spellcasting ability is Charisma (spell save DC 13, +5 to hit with spell attacks). The dragon knows the following spells and can cast them without material or somatic components:
Cantrips (at will): Fire Bolt, Produce Flame
1x/day: Burning Hands

Multiattack. The dragon makes three attacks: one with its bite and two with its tail.

Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 10 (1d10 + 5) piercing damage plus 4 (1d8) fire damage.

Tail. Melee Weapon Attack: +8 to hit, reach 10ft. , one target. Hit. 11 (1d12 + 5) bludgeoning damage.

Smoke Breath. The dragon exhales a suffocating wall of burning smoke in a 30­-foot cone. Each creature in that cone must make a DC 15 Constitution saving throw, taking 49 (11d8) fire damage on a failed save, or half as much damage on a successful one.

Dodge (2x/day). The dragon takes the dodge action as a bonus action. Once the dragon is hit with an attack, the dodge ends.