Null gravity field. The astral dragon can change the direction of gravity within a 60ft radius of themselves whilst within the astral sea.

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

Astral familiarity. The astral dragon has a 8 additional bonus onto their intelligence bonus for calculating how far they can move within the astral sea and manipulating the space around them in the astral sea. 

Detect extraplannar. The astral dragon can sense any creature that is not from the astral plane that is within 90ft of themselves. 

Sever Silver Cord. If the astral dragon scores a critical hit with its bite attack against a creature traveling through the Astral Plane by means of the astral projection spell, the dragon can cut the target's silver cord instead of dealing damage.

Innate Spellcasting. The ancient astral dragon’s innate spellcasting ability is Wisdom (DC 20). The ancient astral dragon can innately cast the following spells, requiring no material components:

3/day each: enhance ability (eagle's splendor only), feeblemind 

1/day: banishment 

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

Bite. Melee Weapon Attack: +14 to hit, reach 15 ft., 1 target. Hit: 20 (2d12 + 8) piercing damage. 

Claw. Melee Weapon Attack: +14 to hit, reach 10 ft., 1 target. Hit: 16 (2d8 + 8) slashing damage. 

Tail. Melee Weapon Attack: +14 to hit, reach 20 ft., 1 target. Hit: 14 (2d6 + 8) 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 20 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.

Breath Weapons (Recharges 5/6). The astral dragon uses one of the following breath weapons.

Banishing breath. The astral dragon exhales a beam of banishing cyan energy, each creature within a 10ft wide, 90ft long line must make a DC 20 Wisdom saving throw or be banished back to their home planes.

Scouring breath. The astral dragon exhales a blast of the scouring astral storm winds, each creature in a 90ft cone must make a DC 20 Constitution saving throw or take 63 (21d6) force damage. Half as much damage on a successful saving throw. 

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

Detect. The dragon makes a Wisdom (Perception) check.

Astral shimmer (Costs 2 Actions). The astral dragon chooses one creature they can see within 60ft of themselves and that creature must make a DC 21 dexterity saving throw or a DC 21 intelligence if they are in the astral sea. On a failed save the target is blinded until the end of their next turn and take 45 (9d10) radiant damage. On a successful save the creature only takes half damage. 

Astral jolt (Costs 2 Actions). The astral dragon teleports 30ft in any direction to a space that isn't occupied by any creature.