Two thousand years ago, there was a war between humans and demons. The human race sacrificed the spiritual cores of eight nine-fold mirror geniuses under the age of 18 and injected them into the national jade seal. They finally defeated the demons and sealed it. Now, the demon clan's seal is loosened, the spiritual power of the national jade seal is disappearing, and the survival of the human race is at stake...
What a great book. Highly recommended.