Artificial Reality Timespaces for Endlessly Maintaining the Ideal Senario (A.R.T.E.M.I.S.) System was an artificial intelligence, capable of reproducing the past and allowing those that enter the opportunity to make the changes necessary for the prosperity of all intelligent life. Accessing the system meant gaining the authority to change history. While Artemis allows the reshaping of history, at the same time it draws and guides the intelligent species to the most ideal future, taking into account the near-infinite number of variables, including the current number and societal status of intelligent life and future technological advance.
The appearance of the shadow world was a result of the Artemis System after suffering significant functional damage. Because of that damage, the system stuck in a loop, continually repeating its calculations while trying to reach the future that is now impossible. The function of reproduction of the past historical events remained, but the power to reshape the past had been lost.
It tried to lead everyone to the best future but no matter what choice it made, the consequences of the destruction of the civilization was always the end. The Artemis system recorded this as the biggest collapse point of humanity.
Although Artemis System was created to advance humanity, but it ultimately became the very thing that threatened and destroyed humanity. It was later revealed that the Artemis system is a piece of technology invented by humans.
Lunia is an artifact which was in the possession of Skull Mask. It was the Artemis Systems support system and contained stored information about the world.
There were four facilities which can run the Artemis System. All three places, except the one located at Hebrion Academy, currently unable to be entered due to an error in the historical reproduction.