Adult Iron Shadow Dragon

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

Shadow Stealth. While in dim light or darkness, the dragon can take the Hide action as a bonus action.

Sunlight Sensitivity. While in sunlight, the dragon has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.

Multiattack. The dragon can make three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) piercing damage plus 6 (2d4 + 1) fire damage.

Claw. Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) slashing damage.

Tail. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 14 (2d8 + 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.

Spark Breath. The dragon exhales super heated sparks in a 60-foot cone. Each creature in that area must make a DC 18 Dexterity saving throw, taking 44 (11d6) fire damage and 15 (3d8) on a failed save, or half as much damage on a successful one. It can use this once per long rest.

Shadow Breath (Recharge 5-6). The dragon exhales shadowy fire in a 30-foot cone. Each creature in that area must make a DC 18 Dexterity saving throw, taking 40 (10d6) necrotic damage on a failed save, or half as much damage on a successful one. A humanoid that dies within 1 minute of being hit by this, and an undead shadow rises from its corpse and acts immediately after the dragon in the initiative count. The shadow is under the dragon’s control.

Sleep Gas Breath (Recharge 5-6). The dragon exhales puffy clouds of smoke in a 30-foot cone. Each creature in that area must make a DC 14 Constitution saving throw. On a fail the creature falls asleep and can make a constitution saving throw on each of it's turns to wake up. On a success the creature is unaffected.

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. The dragon makes a Wisdom (Perception) check.

Tail Attack. The dragon makes a tail attack.

Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 10 feet of the dragon must succeed on a DC 22 Dexterity saving throw or take 15 (2d6 + 8) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.