Earth

Earth is a planet of key importance across the entire Xeno-series. It is the native planet of humanity.

In Xenogears
The history of Earth is virtually identical to how it is in real life until the year 2001 A.D., where the Zohar was discovered. Because of its mysterious properties, some people took to the theory that the Zohar created life on Earth.

Many years later, in 2510 A.D., a project to emigrate out of Earth was set into motion. In 0016 T.C., (2526 A.D.) humanity began to fully emigrate out of the planet, never to return. For unknown reasons, the planet became a forbidden region of space, with its new name of ‘’Lost Jerusalem.’’

Millennia later, when the Eldridge was hijacked by Deus, it began to change course to Lost Jerusalem, referred to by the crew as “the main planet”. The ship did not reach its new destination, with it crash landing on a remote planet in space.

In Xenoblade Chronicles 3
It is revealed by the Queen of Agnus, Nia that Earth was split into the worlds of Bionis and Mechonis and Alrest when Klaus activated the Conduit. Both worlds will inevitably reunite, but doing so will destroy both worlds, known as the Intersection, leaving only light. As the worlds got closer, the Nia manages to make contact with her Kevesi counterpart, Melia for the first time. To prepare for the Intersection, they built an arc from each side, known as Origin to preserve the consciousness of both worlds and reboot them. However the reboot process failed and both worlds fused into Aionios due to Z and Moebius who captured Melia to access Origin's memory banks and take it over. After Z's death, Origin starts up and the world splits back into the two original worlds.