Doomsday Trap

These characteristics of the Gantz server were, in Chen Chen's view, extremely outrageous.

This was a crystal structure that would not change its change no matter how it was destroyed and it was easily replicable. Chen Chen would almost think that there was some conspiracy. 

According to the original plot of the comic, all of Gantz's technology was recounted by the German entrepreneur's daughter. She had this ability because Alien Civilization A was about to be wiped out by Alien Civilization B, so they transmitted their technology to the people on Earth.

The reason for this was that Earth was Alien Civilization B's next target.

This was what happened in this reality. In just a few years, Alien Civilization B came to Earth and waged a war, and the ending was that humans successfully defeated Alien Civilization B by using Gantz's technology.