The Great War (大戦, Taisen), also known at The Eternal War, was a war between all races that began so far in the past that nobody remembers clearly and ended about six thousand years ago. The war was caused by the gods, also known as Old Deus, to obtain the Star Cup, which has the power to do anything and thus the wielder will be crowned the Only God or the True God.
During the war, the sky was bleached red and falling blue ash-like particles covered the land. These were said to be the remains of dead spirits, and were highly poisonous to any part of any living body it came contact with. The world seemed to have been much colder, although still warm enough for humans to survive. It was most likely heated by the surrounding ashes upon the ground since the sun hadn't been seen for thousands of years. The attacks of the stronger races frequently transformed the landscape. Much less animals lived during this time. Humans could only survive by living secretly in caves and sending scouts to scavenge the wreckages left from battles between other races.
- Judging by Azriel's age, the war most likely lasted for around 20,000 years.