Anti-Hide and Seek Crystal

Wondrous Item, Artifact-level ward component

A foot-long pale pink crystal covered in faded etched runes. This crystal is an insanely powerful ward meant to be placed in the socket of a great machine or shrine, not a portable magic item. 

While charged, the crystal suppresses magic from the schools of Divination, Enchantment, and Illusion.

Anti–Hide-and-Seek Aura

While the crystal has charge, it creates a magical aura centered on itself. Any creature inside the aura that casts a spell, activates a magic item, or creates a magical effect from the schools of Divination, Enchantment, or Illusion must make a spellcasting ability check.

The DC depends on the crystal’s current state:

On a failed check, the spell or magical effect fails. If the effect used a spell slot, charge, or limited use, that resource is still expended.

Aura Radius by Charge

The crystal’s aura radius depends on how much stored charge it has.

If the crystal is not installed in a warding socket, divide its aura radius by 2.

Suppressed Magic

The crystal affects spells and effects such as detect magic, identify, scrying, locate object, locate creature, detect thoughts, charm person, suggestion, disguise self, minor illusion, silent image, glamours, magical disguises, magical masks, invisibility-like effects, and similar magic.

The DM decides whether a magical effect is sufficiently tied to Divination, Enchantment, or Illusion to be suppressed.

Charging the Crystal

A creature can use an action to touch the crystal and expend one spell slot into it. The crystal gains stored charge based on the level of the spell slot expended.

Formula:

Stored charge gained in minutes = spell slot level × 10

For example, a 1st-level spell slot gives the crystal 10 minutes of stored charge, while a 9th-level spell slot gives it 90 minutes of stored charge.

The crystal can hold a maximum of 24 hours of stored charge.

Why High-Level Spellcasters Matter

To fully charge the crystal, the required spell slot energy is:

24 hours = 1,440 minutes
1 spell level = 10 minutes
1,440 ÷ 10 = 144 total spell levels

So fully charging the crystal requires 144 total levels of spell slots.

A low-level spellcaster can barely power it. A group of powerful spellcasters, or a very high-level spellcaster with time and resources, can keep it functioning.

Loose Crystal Limitation

When the crystal is not installed in a warding socket, its effective power is halved.

Formula:

Effective charge = stored charge ÷ 2

For example, if the crystal has 1 hour of stored charge, it functions as though it has only 30 minutes of effective charge while loose or carried.

Empty State

When the crystal reaches 0 minutes of charge, it becomes inert. It remains a valuable ancient crystal, but it does not suppress magic until it is recharged.