Sword Art Online - Alicization Manga

Project Alicization is a secret government effort to create the first highly adaptive artificial intelligence. Run by Rath, a company affiliated with the Japan Self-Defense Force, it uses a fourth-generation FullDive machine called the Soul Translator to copy the Fluctlights—the souls—of twelve newborn babies, producing undeveloped artificial Fluctlights known as Soul Archetypes. These copies must be nurtured before they mature into individuals. To raise them, Rath creates Underworld, a virtual world built with the free-kernel version of the Cardinal System, The Seed, and loaded into the Soul Translator’s mainframe. Underworld is set in an age when science and philosophy are only beginning to emerge. Rather than recreate the past, its designers limit the terrain and establish certain customs so its inhabitants can form their own society.