Silha had been undisturbed for thousands of years since the Creators' flight from Earth. The island is constantly surrounded by an electromagnetic field that disrupts any technology within its radius; storms and vortices fill the surrounding sea, destroying any ships that approach. The only human to discover the island was Dr. Hamilcar Barcas (before he was known as such) 400 years before the events of the Guyver series take place. He miraculously survived the destruction of his ship and became stranded on the island, finding it inhabited by all manner of abnormal creatures: giant dragonflies, dinosaurs, even mermaids. As he explored the lush jungles of the island, he came across the temple where Archanfel resided, finding him in suspended animation within an amniotic pod. Barcas immediately found himself in awe of Archanfel and pledged his allegiance to him. Since then, Archanfel and Barcas founded the secret society of Cronos and worked toward the transformation of the entire human race.
To date, the only people on Earth aware of Silha's existence are Archanfel, Dr. Barcas and the two loyalist Zoalords Sin Rubeo Amniculus and Friedrich von Purgstall. In the most recent chapter of the manga, Sho Fukamachi's friends Tetsuro and Mizuki Segawa have found themselves dumped within Archanfel's temple on Silha after being abducted the mysterious being known as Apollyon.