Endless Deep Space

The earth was suddenly attacked by an unknown civilization, and the world was plunged into crisis. Humanity resisted desperately. When the earth's population plummeted, the unknown civilization suddenly left. Why did civilizations with powerful technology suddenly attack the earth, and why did they suddenly leave? This is a war between two advanced civilizations. When one side loses, it attacks the earth to test humans, and chooses humans to inherit their mantles and take revenge on their behalf. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.