The Fall of Gemworld was the final battle in the Earth 2 War. A destructive conflict, it happened mostly following the main course of war on Earth 0. It was the final battle for a long time between the Superheroes of Earth 0 and the Parademon Army, the latter of which was finally bested.
After being defeated on the mainland of Earth 0, the remnants of the Parademon Army regrouped and decided to attack on a different front. Traversing through space and time, the Parademons attacked Gemworld, which was located in a realm known for aiding Earth 0. In their ruthless assaults, Amethyst was forced to call upon the Justice League Dark. Although her face was scarred by Apokoliptan weapons, Amethyst kept fighting, even agreeing to work with John Constantine. The Hellblazer claimed he could stop the remnants, but tricked Amethyst and the JLD, teleportint them back to Earth 0 and jarring Gemworld off. The Parademons proceeded to kill every inhabitant on Gemworld before starving to death, ending the war.
With the Fall of Gemworld, Amethyst vowed to kill Constantine, but also lost her connection to magic, forcing her to become an agent of SHADE. Sacrificing Gemworld also affected Constantine on a personal level, with him being unable to live with the guilt. While Amethyst became much more fierce, Constantine became a much more distant and cowardly person.