Satan created 72 immortal children, each immune to injury unless struck by a weapon forged in hellfire. These children were given weapons and commanded to fight for survival, with the victor becoming the new king of hell. Hagino Sin, the child most despised by Satan, escaped the netherworld. He tricked a kind-hearted writer into taking him in, but his plan backfired when he developed an attachment to the writer and his school friends. Sin must now fight his siblings to survive while trying to retain his newfound humanity.
