Apocalyptic Cataclysm

Apocalypse Aura. At the end of each of the apocalyptic cataclysm's turns, each creature, object, and structure within 20 feet of it takes 18 (4d8) Acid damage plus 18 (4d8) Cold damage plus 18 (4d8) Fire damage plus 18 (4d8) Lightning damage plus 18 (4d8) Thunder damage.

Civilization Ender. The apocalyptic cataclysm deals triple damage to objects and structures.

Legendary Resistance (6/Day). If the apocalyptic cataclysm fails a saving throw, it can choose to succeed instead.

Living Apocalypse. The apocalyptic cataclysm can move through a space as narrow as 1 inch without expending extra movement to do so, and it can enter a creature's space and stop there. The first time it enters a creature, object, or structure's space on a turn, that target takes 18 (4d8) Acid damage plus 18 (4d8) Cold damage plus 18 (4d8) Fire damage plus 18 (4d8) Lightning damage plus 18 (4d8) Thunder damage.

Multiattack. The apocalyptic cataclysm makes up to four attacks, using Blade of the Flood, Blade of the Inferno, Blade of the Quake, and Blade of the Tempest in any combination.

Blade of the Flood. Melee Attack Roll: +19, reach 30 ft. Hit: 27 (5d6 + 10) Bludgeoning plus 27 (5d8 + 10) Cold damage, and the target has its speed reduced by 30 feet.

Blade of the Inferno. Melee Attack Roll: +19, reach 30 ft. Hit: 52 (12d6 + 10) Fire damage and the target is burning until extinguished, taking 10 (3d6) Fire damage at the start of each of its turns.

Blade of the Quake. Melee Attack Roll: +19, reach 30 ft. Hit: 27 (5d6 + 10) Bludgeoning damage plus 27 (5d6 + 10) Thunder damage, and the target has the Prone condition and is pushed 30 feet away.

Blade of the Tempest. Melee Attack Roll: +19, reach 30 ft. Hit: 27 (5d6 + 10) Lightning damage plus 27 (5d6 + 10) Thunder damage, and the target has the Blinded, Deafened, and Stunned conditions.

Spellcasting. The apocalyptic cataclysm casts one of the following spells requiring no spell components, no concentration, instead lasting for the full duration, and using Constitution as the spellcasting ability (spell save DC 27):

At Will: Tsunami, Control Weather, Delayed Blast Fireball, Earthquake

1/Day: Storm of Vengeance

Unleash Apocalypse (Recharge 6). The apocalyptic cataclysm creates one of the following effects of its choice.

Flood. Strength Saving Throw: DC 27, each creature, object, and structure within 120 feet of the apocalyptic cataclysm. Failure: 45 (10d8) Bludgeoning damage plus 45 (10d8) Cold damage and the target has the Prone condition. Success: Half damage only. Failure or Success: The target's speed is reduced to 0 until the start of its next turn.

Inferno. Dexterity Saving Throw: DC 27, each creature, object, and structure within 150 feet of the apocalyptic cataclysm. Failure: 91 (26d6) Fire damage. Success: Half damage only. Failure or Success: The target is burning until extinguished, taking 10 (3d6) Fire damage at the start of each of their turns.

Quake. Constitution Saving Throw: DC 27, each creature, object, and structure within 300 feet of the apocalyptic cataclysm. Failure: 44 (8d10) Bludgeoning damage plus 44 (8d10) Thunder damage, and the target has the Prone condition, and its Concentration is broken. Success: Half damage only.

Tempest. Dexterity Saving Throw: DC 27, each creature, object, and structure in a 150-foot-radius, 500-foot-high Cylinder centered on the apocalyptic cataclysm. Failure: 45 (7d12) Lightning damage plus 45 (7d12) Thunder damage, and the target is moved 30 feet in a direction of the apocalyptic cataclysm's choice. Success: Half damage only.

Legendary Action Uses: 3. Immediately after another creature's turn, the apocalyptic cataclysm can expend a use to take one of the following actions. The apocalyptic cataclysm regains all expended uses at the start of each of its turns.

Destructive Movement. The apocalyptic cataclysm moves up to its movement speed without provoking opportunity attacks and makes one attack from the Multiattack options.

Teleport. The apocalyptic cataclysm teleports to a point it can see within 120 feet of it.

Destroy (3 Legendary Actions). The apocalyptic cataclysm focuses its ire on one target it can see within 120 feet. That target must make a DC 27 Constitution saving throw. On a failed save, the target takes 80 (32d4) damage of a type chosen by the apocalypse elemental: Acid, Cold, Fire, Lightning, or Thunder.