The Nucleus of the Spheres
by WingofCootArtifact
This artifact has no random powers or side effects. Its only power is serving as the source of the Radiance; its side effects are a deadly field of Radiance energy and (before the events of Wrath of the Immortals) a slow drain of magic from the world of Mystara.
Source of Radiance. Radiance Foci, and spells with RF components, can only be used within 500 miles of the Nucleus of the Spheres. The power weakens with distance; the maximum possible Radiance Bonus that can be applied to Radiance spells is +4 within 30 miles of the Nucleus, +3 from 30 to 50 miles distance, +2 from 50 to 120 miles distance, and +1 beyond 120 miles distance. This artifact is far too large to move, and is permanently located in a cavern (with no existing entrance) 10,000 feet under Glantri City.
Deadly Field. Any creature in the cavern of the Nucleus of the Spheres must make a DC 15 Constitution save each round or suffer 12d10 radiant damage. A creature reduced to 0 hit points by this damage becomes a lightning zombie.
In addition, a creature which fails any of these saves suffers an extreme form of Radiance Sickness. While affected, the creature is poisoned, and this poisoned condition cannot be removed by normal means such as Lay on Hands, lesser restoration, or protection from poison. Only a heroes' feast, wish, or other spell of 6th level or higher which removes the poisoned condition will work.
Conversion Note: The 500-mile range to use Radiance spells comes from Robin's work here