Ten thousand years ago, apes evolved into a sapient primate species: humanity. A thousand years ago, animals gradually awakened to thought. People had hoped the two sides would live together in peace, but humanity, arrogant in its belief that it ruled all living things, kept the newly enlightened animals under its thumb. At last, the First World Species War broke out in 1914, followed by the Second in 1939. In 2010, the Fourth World Species War erupted once again. Humanity and the animals waged war time and again, divided by the distinction between their own kind and the other... Countless ordinary people were swept into this brutal conflict, becoming tragic casualties of the march of history. As the war grew ever worse, governments around the world resorted to biological weapons, and the entire globe was ultimately transformed into a hellscape at the end of the world. A few islands in the seas off the Eastern Continent became home to the survivors. But to stay alive, they must reopen the lifeline connecting them to the mainland.
