Celestial Archdragon

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

Celestial Form: The Celestial Dragon’s body glows faintly, as if lit from within by starlight. Its scales shimmer with shifting colors, resembling the night sky or the surface of a distant galaxy.

Eyes of Eternity: The dragon's eyes appear as swirling nebulas, giving off an intense and calming radiance. Looking into them can evoke feelings of awe, humility, or even fear of the infinite.

Wings of the Cosmos: Its immense wings are semi-transparent and flecked with constellations, leaving trails of light as they move. When fully unfurled, they seem to stretch beyond the limits of space itself.

Aura of Balance: The air around the dragon hums with energy, and a faint halo of light surrounds it, shifting in hue based on the dragon's mood or the state of cosmic balance.

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

Bite. Melee Weapon Attack: +17 to hit, reach 15 ft., one target. Hit: 21 (2d10 + 10) piercing damage.

Astral Claw Effect: The Celestial Dragon makes a melee weapon attack with its claws. On a hit, the target takes 35 (6d8 + 10) slashing damage plus 18 (4d8) radiant damage, and the target must succeed on a DC 20 Constitution saving throw or have their speed reduced to 0 until the end of the dragon's next turn.

Tail. Melee Weapon Attack: +17 to hit, reach 20 ft., one target. Hit: 19 (2d8 + 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 21 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.

Celestial Breath (Recharge 5–6) Effect: The Celestial Dragon exhales a blast of stardust and raw astral energy in a 90-foot cone. Creatures in the area must make a DC 22 Dexterity saving throw, taking 88 (16d10) radiant damage on a failed save, or half as much on a successful one. Any creature that fails its saving throw is blinded for 1 minute.

Starfall (Recharge 6) Effect: The dragon summons meteors from the heavens, which fall in a 30-foot radius centered on a point it can see within 150 feet. Each creature in the area must make a DC 22 Dexterity saving throw or take 56 (8d10) fire and radiant damage, or half as much on a successful save.

Cosmic Grasp (Recharge 5–6) Effect: The dragon creates a massive hand of cosmic energy that reaches out and grabs a creature within 60 feet. The target must make a DC 20 Strength saving throw or be restrained. The target can repeat the saving throw at the end of each of its turns, breaking free on a success. While restrained, the creature takes 18 (4d8) force damage at the start of the dragon’s turn.

Astral Shift: Effect: The Celestial Dragon can momentarily blur its form, appearing to shift between planes. It can teleport up to 30 feet to an unoccupied space it can see, without provoking opportunity attacks.

Stellar Echo Effect: The dragon momentarily releases a burst of cosmic sound, disorienting its enemies. Each creature of the dragon’s choice within 15 feet must succeed on a DC 20 Wisdom saving throw or be stunned until the start of the dragon's next turn.

Cosmic Rejuvenation Effect: The dragon taps into the vast energy of the cosmos, healing itself for 30 hit points. This ability can only be used once per short or long rest.

Planar Ward Effect: The Celestial Dragon calls upon the celestial planes to bolster its defenses. Until the start of its next turn, it gains resistance to one damage type of its choice (fire, cold, lightning, or radiant).

Starflare Effect: The dragon releases a flash of starlight, blinding a creature of its choice within 60 feet for 1 round. The target must succeed on a DC 20 Constitution saving throw or be blinded.

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 archdragon makes a Wisdom (Perception) check.

Stellar Gaze (Costs 2 Actions) Effect: The archdragon targets one creature it can see within 60 feet. The target must succeed on a DC 22 Wisdom saving throw or become frightened for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on a success.

Cosmic Shield (Costs 3 Actions) Effect: The dragon surrounds itself or an ally within 30 feet with an aura of shimmering stardust. The target gains resistance to all damage types until the start of the dragon’s next turn.

Wing Attack (Costs 2 Actions). The archdragon beats its wings. Each creature within 15 feet of the dragon must succeed on a DC 25 Dexterity saving throw or take 17 (2d6 + 10) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.

 Stellar Rebirth (Costs 3 Actions) Effect: The dragon channels the vast energy of the cosmos and regains 100 hit points. After using this action, the dragon’s next attack deals an additional 18 (4d8) radiant damage.

Cosmic Apocalypse (Costs 5 Actions) Effect: The dragon creates a catastrophic rift in the fabric of reality, causing a 60-foot radius around it to become unstable. Each creature in the area must make a DC 24 Dexterity saving throw or take 112 (16d10) radiant damage and be knocked prone. Creatures that succeed on their saving throw take half damage and are not knocked prone.