Project Alicization

Project Alicization is a top-secret government project run by RATH using the fourth generation FullDive technology, Soul Translator. Their goal is to create perfect Artificial Intelligence by simulating their live as an NPC in virtual reality. What's special about these AIs is that they "learn" as a human does. While RATH's end-goal is to use these AIs to fight in wars instead of humans, the virtual world they are raised in prevents them from breaking even the most insignificant of laws, especially killing another. The virtual world that houses these AIs is called, by the creators, Underworld: the name may or may not be connected to the original name of Alice's Adventures in Wonderland; Alice's Adventures Under Ground. The facilities that have connections to it are in Roppongi and the Ocean Turtle (A marine base that kind of looks like the Mock Turtle from the story).

For experimentation purposes, RATH inserts Kirito into the Underworld and, to their surprise, the people who interacted with Kirito were closer to breaking the rules than any others. After allowing the experiment to continue for a while, a girl, that by coincidence is named Alice, finally breaks one of the cardinal rules in the world.