Temple of Null (5e Equipment)
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Wondrous item, artifact (requires attunement by a worshiper of Aakronus)
an ancient relic said to be wielded by a high cleric of Aakronus during his conquest of the realms, this ancient relic disables all magical forces near it, creating a field of grey light.
Antimagic Field. In its inactive form, the temple resembles a 2 inch by 4 inch block of grey crystalline material. When activated, the block expands to a pyramid with a base area spanning 900 square feet and measuring 800 feet tall. Any creature within 2 kilometers of this temple must make a DC 15 saving throw of their spellcasting ability whenever attempting to cast a spell, with the spell functioning normally on a success and not functioning at all on a failure, all creatures also have an advantage on saving throws against spell effects,any constructs or undead of CR 10 or higher are destroyed instantly, and magical items of rare or lower rarity do not function. The temple is active for as long as at least one creature has concentration on it. Multiple creatures can be concentrating on the temple at a time and only need attunement to activate it.
Destroying the Temple of Null. If the one attuned to the temple is killed, the temple expands and contracts rapidly before collapsing in on itself, creating a 200 foot sphere of energy, dealing 5d20 necrotic damage and 5d20 radiant damage to any creature caught in its blast.