Adult Red Shadow Dragon

Living Shadow- While in dim light or darkness, the dragon has resistance to damage that isn't force, psychic, or radiant.

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. 

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

Multiattack- The dragon can use its Frightful Presence. It then makes three attacks; one with its bite and two whit its claws. 

Bite- Melee Weapon Attack: +16 to hit, reach 15 ft., one target. Hit: (2d10+10) piercing damage plus (4d6) necrotic damage. 

Claw- Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: (2d6+10) slashing damage.

Tail- Melee Weapon Attack: +17 to hit, reach 20 ft., one target. Hit: (2d8+10) bludgeoning damage. 

Frightful Presence- Each creature of the dragon's choice that is within 120 ft of the dragon and aware of it must succeed on a DC 21 Wisdom saving throw or become frightened for one 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 twenty four hours. 

Shadow Breath (Recharge 5-6)- The dragon exhales shadowy fire in a 90-foot cone. Each creature in that area must make a DC 24 Constitution saving throw, taking (26d6) necrotic damage on a failed save, or half as much damage on a successful one. A humanoid creature reduced to zero hit points by this damage dies, and an undead shadow rises from its corpse and acts immediately after the dragon in the initiative count. The shadow is under the dragons control. 

The dragon can take three 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 creatures 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 two actions)- The dragon beats its wings, each creature within 15 feet of the dragon must succeed on a DC 25 Dexterity saving throw or take (2d6+10) bludgeoning damage and be knocked prone. The dragon covers the area with smoke and can then fly up to half its flying speed.