The Sutra says: When the heaven and earth first opened, all things reincarnated among the six paths: one is the path of gods, the second is the path of the world, the third is the path of asuras, the fourth is the path of beasts and monsters, the fifth is the path of souls, and the sixth is the path of the underworld.
Everything, life and death, comes and goes.
The cycle begins again and again, so it is called the Six Paths of Reincarnation!