Asgorath

Legendary Resistance (4/Day). If the greatwyrm fails a saving throw, it can choose to succeed instead. Unusual Nature. The greatwyrm doesn’t require food, drink, sleep or breathe.

Divine Awakening (Recharges after a Short or Long Rest). If the greatwyrm would be reduced to 0 hit points, its current hit point total instead resets to 425 hit points, it recharges its Breath Weapon, and it regains any expended uses of Legendary Resistance. Additionally, the greatwyrm can now use the options in the “Mythic Actions” section for 1 hour. Award a party an additional 105,000 XP (210,000 XP total) for defeating the greatwyrm after its Divine Awakening activates.

Mass Telekinesis (Divine Awakening Only; Recharges after a Short or Long Rest). The greatwyrm targets any number of creatures and objects it can see within 120 feet of it. No one target can weigh more than 4,000 pounds, and objects can’t be targeted if they’re being worn or carried. Each targeted creature must succeed on a DC 26 Strength saving throw or be restrained in the greatwyrm’s telekinetic grip. At the end of a creature’s turn, it can repeat the saving throw, ending the effect on itself on a success. At the end of the greatwyrm’s turn, it can move each creature or object it has in its telekinetic grip up to 60 feet in any direction, but not beyond 120 feet of itself. In addition, it can choose any number of creatures restrained in this way and deal 45 (7d12) force damage to each of them.

Multiattack. The aspect makes one Bite attack and two Claw attack,. 

Bite. Melee Weapon Attack: +15 to hit, reach 20 ft., one target. Hit: 23 (3d12 + 10) piercing damage plus 19 (3d12 + 3) force damage.

Claw. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 21 (2d12 + 7) slashing damage. If the target is a Huge or smaller creature, it is grappled (escape DC 20) and is restrained until this grapple ends. The aspect can have only one creature grappled this way at a time.

Breath Weapon (Recharge 5-6). The greatwyrm uses one of the following breath weapons at random. Roll 1d6:

Psionic Breath (1 or 2). The greatwyrm exhales crushing force in a 300-foot cone. Each creature in that area must make a DC 25 Dexterity saving throw. On a failed save, the creature takes 116 (12d12 + 25) force damage and is knocked prone. On a successful save, it takes half as much damage and isn’t knocked prone. On a success or failure, the creature’s speed becomes 0 until the end of its next turn.

Divine Breath (3 or 4). The greatwyrm exhales a blast of energy in a 300-foot cone. Each creature in that area must make a DC 25 Dexterity saving throw. On a failed save, the creature takes 155 (12d20 + 30) elemental damage of a type determined by the greatwyrm.

Sapping Breath (5 or 6). The greatwyrm exhales gas in a 300-foot cone. Each creature in that area must make a DC 25 Constitution saving throw. On a failed save, the creature falls unconscious for 1 minute. On a successful save, the creature has disadvantage on attack rolls and saving throws until the end of the greatwyrm’s next turn. An unconscious creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Change Shape. The greatwyrm magically transforms into any creature that is Medium or Small, while retaining its game statistics (other than its size). This transformation ends if the greatwyrm is reduced to 0 hit points or uses a bonus action to end it.

Psychic Step. The greatwyrm magically teleports to an unoccupied space it can see within 60 feet of it.

The greatwyrm 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 greatwyrm regains spent legendary actions at the start of its turn. Attack. The greatwyrm makes one Claw or Tail attack.

Psionics (Costs 2 Actions). The greatwyrm uses Psychic Step or Spellcasting.

Wing Attack (Costs 2 Actions). The greatwyrm beats its wings. Each creature within 30 feet of it must succeed on a DC 26 Dexterity saving throw or take 17 (2d6 + 10) bludgeoning damage and be knocked prone. The greatwyrm can then fly up to half its flying speed.

Arcane Spear (Costs 3 Actions). The greatwyrm creates four spears of magical force. Each spear hits a creature of the greatwyrm’s choice it can see within 120 feet of it, dealing 12 (1d8 + 8) force damage to its target, then disappears.

Psychic Beam (Costs 3 Actions). The greatwyrm emits a beam of psychic energy in a 90-foot line that is 10 feet wide. Each creature in that area must make a DC 26 Intelligence saving throw, taking 27 (5d10) psychic damage on a failed save, or half as much damage on a successful one.

If the greatwyrm’s Divine Awakening trait has activated in the last hour, it can use the options below as legendary actions.

Chromatic Flare (Costs 2 Actions). The greatwyrm flares with elemental energy. Each creature in a 60-foot-radius sphere centered on the greatwyrm must succeed on a DC 26 Dexterity saving throw or take 22 5d8 damage of a type determined by the greatwyrm’s kind: acid (black), cold (white), fire (red), lightning (blue), or poison (green).

Shattering Roar (Costs 2 Actions). The greatwyrm unleashes a magical roar. Each creature in a 120-foot-radius sphere centered on the greatwyrm must succeed on a DC 26 Constitution saving throw or take 19 (3d12) thunder damage and be incapacitated until the end of its next turn.