The Protectors [BTS FF]
Long ago, an evil force arose from the depths of hell, then there were 8 protectors, they were blessed by the king of heaven with extraordinary power. They were told to be the ones who can bring down the evil force. But because the protectors were already wounded severely, they couldn't banish the demons into hell forever, they had to sacrifice their life to be able to close the crack completely.
Back to the present, the 7th king of earth had a vision stating that the demons of hell are to come back to earth in attempt to take over again! Aside from that, he also had another vision saying that the 8 protectors' souls were hidden among 8 teenagers..