When the Kami fell from Tengoku, Fu Leng fell through Ningen-do and into Jigoku. Exposure to the realm of evil drove the ninth Kami insane but also gave him great power. After returning to Ningen-do, Fu Leng began to destroy his siblings' empire in a fit of jealousy. Thus the First War, also known as the War Against Fu Leng began, lasted many years until the first Day of Thunder.