The Ritual of the Waning Moon is initiated three days before the new moon, culminating on the night the moon is darkest. A crystal ring (quartz or even glass will do) is charged with a single use of the Invisibility spell. Until discharged, the Ring of the Waning Moon reflects the phase of the moon: dark at new moon, bright but not glowing at full moon, band shaded proportionately in between.
When activated by its wearer, the wearer becomes invisible as if a waning moon — fully visible, then fading from one side to the other until invisible — over one round. At the end of the round, the spell has been discharged. The spell otherwise behaves normally.
The charge lasts until the full moon before the new moon one year after the ritual, unless discharged sooner. Once discharged, the invisibility lasts 1d6 * 10 minutes, as normal.
The crystal ring can be reused as a ritual focus, and can be charged again.
There are rumors of a Ritual of the Setting Sun that is faster but produces more transient results, taking only a single day and completing at sundown. The visual effect is more like a setting sun: the wearer emits light (as the spell) that sinks toward the ground over the course of a round, at which point the wearer is invisible. This ritual can be done any day, but a Ring of the Setting Sun lasts only a month before the charge dissipates.
It is thought that the Ritual of the Occulted Moon, taking seven days to complete and ending on a lunar eclipse, could instead create a Ring of the Occulted Moon. This likely works like a Ring of the Waning Moon, but the wearer gains the benefit of Greater Invisibility, lasting 2d6 rounds.
Finally, legends tell of a Ritual of the Occulted Sun. This ritual takes a month of days, and culminates at a solar eclipse. The ritual ends at the ecliptic totality, at which point the ritualist completes the ritual while staring at the eclipse through the newly-enchanted Ring of the Occulted Sun. It is uncertain whether this truly is a way to create a Ring of Invisibility… or just to ensure the ritualist never sees the ring again.
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