After the apocalypse of 2042 where many types of beings that looked like monsters out of story books appeared.
Human's called them magical beings, they attack humans indiscriminately. Human's relying on technology to fight this new menace discover that things like gun can’t fight the Magical Beings the people of the world fall into despair.
But one day a person invents a mana stone. This stone fuses with a person's soul which enabled human's to use a new type of energy which they called mana which was effective against the Magical Beings the world rejoiced that they had hope once more. With more research it is discovered that everyone's mana is different because everyone's soul is different.
In the year of 2069 a war with the the Magical Being's start, the humans lead by 7 hero's fight the demon which is the most dangerious type of demons.the demons were pushed back but the world mourns the many casualty's of the war.
For the next 10 year's there is peace, mankind rebuilds the world but the human race knows that peace is ever fleeting. So human's create a school to teach the next generation of mankind children they teach these children subject's from the old world and the new, they train them to fight the Magical Beast's and drill in the knowledge of mankind
But one day on the year of 2079 a hero adopts a child that has been experimented on by a scientist, the hero doesn't know but this child will change the fate of the world.