Vaetheo the Adamantine Dragon

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

Stone Camouflage. The dragon Dexterity (Stealth) checks made to hide in rocky terrain. 

Obvious Leadership. All other dragonkin automatically fail Charisma (Intimidation) checks towards the dragon. 

Shattering Demise. When the Adamantine dragon is killed it explodes into razor-sharp spikes of adamantine. Treat the area where these spikes hit the ground like a spike growth zone that does 3d8 piercing damage (This damage is magical).

Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite or tail and two with its claws.

Bite. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit:  3d10 + 10 piercing damage. 

Claw. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit:  3d6 + 10 slashing damage.

Tail. Melee Weapon Attack: +13 to hit, reach 20 ft., one target. Hit:  3d8 + 10 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 22 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 saving throw is successful or the effect ends for it, the creature is immune to the dragons Frightful Presence for the next 24 hours. 

Breath Weapon (Recharge 5-6). The dragon uses one of the following breath weapons.

Time Stop Breath. The dragon exhales Time Stop in a 30-foot cone. Each creature in that area is subjected to the effects of the Time Stop spell.

Negative Energy Breath. The dragon exhales a deadly black mist of negative energy in a 40-foot cone. Each creature in that area must make a DC 22 Constitution saving throw, taking 8d8 necrotic damage on a failed save, or half as much on a successful on. If the Mist kills a target and they failed their constitution saving throw the dragon can choose to raise them as a skeleton or zombie under the dragon's control, otherwise their body but not their possessions crumble to dust. If a target is a plant creature or a magical plant, it makes the saving throw with disadvantage.If a nonmagical plant that isn't a creature, such as a tree or a shrub is in the area of effect it simply withers and dies. Any undead in the area of effect heal 4d10 hp

Adamantine dragons have advantage on opportunity attacks made while in dim light or darkness

Adamantine Dragons 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 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 2 Actions). The dragon beats its wings. Each creature within 15 feet of the dragon must succeed on a DC 22 Dexterity saving throw or take 3d6 + 10 bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.