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. Although Raven managed to defeat her, the rift plane collapsed in the process. With guidance from Gade and Cyanea, Raven managed to escape the Rift Plane in time.
Illumina has a rather basic layout, consisting of five or nine large platforms joined together by large, molten vines/rivers of crystal-like substance. Under the five-platform layout, it is arranged in a diamond shape.
The path Raven uses to escape Illumina is littered with spikes that can damage her if she strays into them, although Gade and Cyanea will present a safe path for her to use.