This is a world with two sides, where yin and yang remain in balance. When a good person dies, another good person is born. When a bad person dies, a good person turns bad.
The demon kings in this world are all heroes who defeated the previous demon king. Their task is to take the demon king's place and commit evil until the next hero arrives to kill them, freeing them at last.
The dragon slayer must become a dragon. In this world, it is inevitable.
