For those who have not completed games in the Xenoblade Chronicles series, this page contains spoilers regarding the plot. Discretion is advised.
The Great Void is a location in Xenoblade Chronicles 2. It is an abyss in the Cloud Sea that surrounds the World Tree. It came into existence at the end of the Aegis War, and was carved from the Cloud Sea by Ophion in order to prevent travelers from reaching the World Tree.
It cannot be visited in gameplay.
When Jin and Malos capture Pyra and hold her in the Cliffs of Morytha, Ophion tries to destroy Malos; however, Malos is able to take control of Ophion and use it to fight against Siren when the party arrives to rescue Pyra. In the battle, both Artifices are destroyed, and as a result, the Great Void quickly begins to disappear.