Ouroboros Ark

The Ouroboros Ark is an ark on which the entirety of the human race had been condensed as computer programs to finally reach eternity. It started the entirety of Mother Justice 's storyline by "falling" on the land of Mother Earth, allowing its inhabitants to discover and retrieve Ristaccia ; its remains lie in the Skyship Ruins. In reality, the fall of the Ark was just what happened from the inhabitants' point of view ; what "actually" happened was all caused by Joah, who was Ana possessed by Ristaccia. She consequently created Paula as L'erisia as the embodiment of all of these losts elements of humanity.

As for the remains themselves, they are known as the "Skyship Ruins" or "Ristaccia Ruins", and many events take place inside them - such as Malchut's defeat, or the final showdown.