Satanophany by Yoshinobu Yamada is a graphic suspense manga featuring extreme violence and sexual themes centered on the "Medusa Syndrome" phenomenon. The plot follows Chika Amagi, who is confined to a prison where inmates are transformed into assassins through psychological manipulation. Critics and readers often describe the series as "quality trash," praising the artwork while warning of intensely graphic, "nightmare fuel" content. As of 2026, the series has surpassed 300 chapters, with over 36 volumes published. For a detailed summary of the plot, you can explore the information on the Wikipedia entry.