Illumina is a location in Another Story - Raven's Choice. It was a rift plane comprised of the elements of Light and Darkness that supported it and resided at, after fleeing there from having escaped the Ark.
After a battle to claim five territories for the Light, it manifested into a physical embodiment of the element, Lumino. Once he was defeated, Raven had to claim nine territories for the Darkness in order to awaken Tenebria, the physical embodiment of darkness. Raven was able to defeat her in battle also, but this caused the rift plane to collapse. With guidance from Gade and Cyanea, Raven managed to escape from the Rift Plane.
The layout of Illumina is incredibly basic; it is simply 5 to 9 large platforms joined together by what appear to be extremely thick, orange vines. With 5 platforms, it is arranged in a diamond shape. The path in which Raven must use to escape Illumina is littered with spikes that can damage her if she strays into them, though Gade and Cyanea will clear a safe path for her to use.