The Rainbow Curtain refers to a set of effects brought on by what had occurred during a period of time when the Rainbow Crystal is actively being used by someone. The Rainbow Curtain's effects first began after Mogo, the first user of the Rainbow Crystal, began to use the Rainbow Crystal to defend her people.
The Rainbow Curtain caused anyone within its region of effect to be born mostly lacking pigment throughout their entire body, the only colorful parts of them being their internal flesh and the sclera of their eyes.
The Rainbow Curtain caused multiple environmental phenomena, the most notable one being the thick cloud cover that covers its entire region of effect.
Most foliage within the range of the Rainbow Curtain takes on a dead looking tone.
Temperatures on the surface within the Rainbow Curtain often are low, and several species moved underground to take advantage of geothermal vents that warmed the caves.
The Rainbow Curtain allowed Demons to freely teleport to the surface at any time, they began constructing multiple portals to Hell, and after the effects of the Rainbow Curtain stopped, they were still able to move between these locations using the portals they had built.