Year 2079 after the apocalypse at 2042 where many monster appear attack human indiscrimanately , technology doesn't useful to fight the demon then a person invent a mana stone .That stone by share a person soul can summon a mana which can be use for fight the demon .each mana is different cause each person have different soul.At 2059 A war with the demon start ,human lead by 7 hero fight the demon with many casualty finally the demon was push back. Then peace comeback for 20 years human have peace but the peace doesn't last for eternity .so human create a school to teach a child a knowledge,to train them, to defeat demon and teach subjects like the old school(lol).then a hero adopt a child that is experiment by a scientist, but the hero doesn't know that child will change the world fate.