Armageddon

You invoke the terminal principle of destruction—an apocalyptic force that collapses life, matter, and magic into oblivion.

Choose a point you can see within range. A 120-foot-radius sphere of catastrophic energy erupts there, warping reality and calling down ruin.

Each creature in that area must make a Constitution saving throw. On a failed save, a creature takes 13d10 force damage + 13d10 necrotic damage, and its maximum hit points are reduced by an amount equal to the necrotic damage taken until it finishes a long rest.

On a successful save, the creature takes half as much damage and suffers no hit point maximum reduction.

Constructs, undead, celestials, and objects automatically fail this saving throw.

The blast leaves behind a zone of ruin:

The area becomes difficult terrain and nonmagical structures and unattended objects take 100 force damage.

Magical effects of 6th level or lower in the area are immediately dispelled.

If a creature is reduced to 0 hit points by this spell, its body destabilizes in destructive feedback. A creature destroyed this way cannot be restored to life except through True Resurrection, Wish, or similarly powerful magic.