Quoted from TokhaarGol Void maiden CYOA:

“Do not panic lumenus one, the blackness which surrounds you is not dangerous, you are not dead, far from it. As we speak your body is being remade to better accommodate your newfound powers. Your existence for the moment is… Complicated to explain. But do not worry you will be made corporal once again.

Allow me to explain the situation you’re in. A long time ago the multiverse was created by a mysterious entity know as The Goddess. To safeguard her creation the goddess created powerful soldiers which could traverse the multiverse, magical girls. She called them Star Guardians. All beings possesses an anima core or as you would call it a soul. A magical girl processes an extremely bright anima core and are able to use magical abilities fuelled by anima, life force. Because the overwhelming majority of beings with bright anima cores are female, they are referred to as magical girls. You are a magical girl. A magical girl’s power grows over time with use, like that of an expanding star. At the apex of a magical girl’s power, her magical abilities will transcend that of gods. But an expanding str will eventually collapse under its own weight and become a black hole. When a magical girl goes supernova, she releases so much power that an entire universe is destroyed. This is not a flaw on the Goddess part, she designed this cruel fate for her celestial soldiers. For there exists a da rans terrible entity with an endless hunger, it wishes to devour all of creation and remake it in it’s own twisted image. It is a realm that exists beyond our understanding, it is The Abyss.

After a lifetime of servitude it is the destiny of every Star Guardian to be thrown in The Abyss to temporarily satiate it’s endless hunger and prevent The Abyss from devouring the multiverse. In The Abyss magical girl are drained of their power and slowly transformed into Abyssal Girls, lewd parasitic eldritch abominations who are as twisted as The Abyss itself. Some magical girls where not content with their destiny. They rebelled against The Goddess and became known as the Void Maidens. Trough countless of experiments The Void Maidens found a method to cheat fate. By mutating and altering parasites from The Abyss. These altered parasites are used by Void Maidens. The feed on our pleasure and anima, they keep our anima cores form burning too bright. The excess pleasure and anima is converted into energy called Xes. Xes is used to fuel a Void Maiden’s magical powers.”