Continual darkness

Continual darkness was an alteration spell that created an area of perpetual darkness impermeable to normal light. The reverse of this spell, continual light, created a permanently sun-bright area.

Effects
The effects of this spell were similar to darkness, creating an area of no light up to 120 ft (36.6 m) away surrounding a central point out to a 60 ft (18.3 m) radius. It could be cast at a point in the air, onto an object, or possibly a creature. If successfully cast on the visual organs of a creature, it was effectively blinded. The spell was permanent until dispelled by the caster, a dispel magic spell, or an equal or stronger light spell was cast on it.

The illusionist version of this spell had half the range and half the radius of the divine version, and was not reversible (although they were able to cast a separate continual light spell).

Continual darkness countered light spells of equal or lesser power, and vice versa.

This spell eventually consumed the material it was cast upon, but dense, hard, or expensive materials (like gems) could last hundreds to thousands of years.

Sinhala stones were known to prevent magical darkness.

Components
The divine version of this spell only required verbal and somatic components to cast. The material component was the substance it was cast upon: air, an object, a structure, or a creature. For the illusionist version, a tuft of bat fur and either a drop of pitch or a small chunk of coal was needed in addition to verbal and somatic components.

History
The reverse of this spell, continual light, was attributed to Netherese arcanist Polybeus in -1164 DR and was originally called Polybeus's illumination.