The Void has existed as a counter to the infinite number of possibilities that make up the multiverse. Where there is everything, there is also nothing. The Void grew a consciousness, wanting to know how everything works since it knows how nothing works.
Fortune smiled on the Void’s consciousness as a dead woman called Heather tried to make another Apocalypse Driver to resurrect herself with a fully functioning body. Something went wrong for Heather and she was still dead.
The genetic lock for Lacey was used to house the Void’s consciousness and make a new body for it. It resulted in a clone of Lacey being born and the original powers of the Apocalypse Driver changing to those of the Void. With a new body, the Void could safely explore everything. It even gave its new body a name, Sandra Noman. Now, she is in training to get her powers under control as Kamen Rider Void.