This ancient crystal prism is diamond in shape, with plates of iron and adamantine affixed to its outside. It was originally commissioned by the mage-kings of the ancient coalition that caused the Ebony War in the hopes that it could be used to maintain the wards they put upon their cities without the focus of an archmage. However, it was never finished because it never reached the mages at the coalition that were meant to complete it.

A spellcaster of 17th level or higher can spend 1 hour engraving runes into the iron plates, finishing the prism’s enchantment. When they begin, they choose one of the following options. If the enchanting is incomplete and a person engraving the device wishes to choose a different option from the one already chosen, they must first spend an amount of time equal to half the time already taken to engrave the plates to erase the pre-existing runes.

Divine Denial. No creature made of or possessing divine magic can enter within 10 miles of the device or teleport into that area. Additionally, no effect created by such a creature can penetrate the area. All such creatures within the area when this effect is activated are flung up to a mile away outside of the border of the area. If they cannot be flung effectively, they are instead teleported to a random unoccupied space within a mile outside of the border.

Universal Denial. All magic not created by artifacts within 10 miles of the device ceases to function, as with the [Tooltip Not Found] spell. There is a 50-foot radius sphere centered on the device that remains unaffected.

Shield of Denial. A barrier appears, forming a wall in a 3-mile radius sphere. The barrier is opaque from the outside, but transparent on the inside. Nothing can pass through the barrier from either side. The barrier can’t be damaged.

Arcane Denial. Whenever a spell is cast within 3 miles of the device, that spell is targeted with a counterspell (add +5 to the roll).

Divinatory Denial. No divination, telepathy, or message-sending magic can enter or exit a radius of 5 miles from the device.

The device is Small, and can be targeted as a creature while active. It is immune to psychic, poison, necrotic, radiant, and fire damage, as well as resistant to nonmagical bludgeoning, slashing, and piercing damage. It has 100 hit points and, having adamantine plating, any critical hit against it counts only as a regular hit. While inactive, the device’s AC is 18. While active, its AC is 23.

The device can be deactivated with a DC 30 Intelligence (Arcana) check over the course of 1 minute, which causes the apparatus to become nonmagical. If this check fails, the creature making the check takes 10d10 force damage, is pushed back 30 feet, and is knocked prone. If this damage reduces the creature to 0 hit points, it dies and its body is turned to dust.

If the device is destroyed, its effect ends if it had one active, and each creature within 30 feet of the device must make a DC 20 Dexterity saving throw. On a failed save, a creature takes 10d10 force damage and is pushed back a number of feet equal to 2d4 times five, or takes half as much damage and is pushed only half as far on a successful save.