Armageddon

You summon the destructive forces of the cosmos, unleashing an apocalyptic event within the area of effect. The very fabric of reality is torn asunder, turning the land itself into a charred wasteland. Every creature and structure within the area suffers tremendous devastation.

A deafening roar echoes through the area as the ground trembles violently. Each creature that fails a Dexterity saving throw takes 20d12 bludgeoning damage, 20d12 fire damage, 20d12 radiant damage, and 20d12 necrotic damage. Half as much damage on a successful save.

In addition to this devastating force, the ground cracks open, releasing torrents of elemental chaos. The area becomes difficult terrain covered in jagged rocks and fissures for 1d4 months, making it hazardous to traverse.

Any structures, buildings, or objects within the area are instantly destroyed, leaving only ruins in their wake. The devastation caused by this spell is immense, even altering the landscape permanently.

Once you cast this spell, you cannot cast it again

Note: The spell "Armageddon" is an incredibly powerful and destructive spell, befitting its name. It is crucial for the Dungeon Master and players to discuss its inclusion in the campaign, taking into account the potential consequences and narrative impact it may bring.