There's a legend that long ago that this world was made by three Gods the God of Light,
the God of Darkness, and the God of Nothing. These three Gods created the universe and our world with it. But long ago those three Gods died and were all reincarnated on our world they all caused an uproar because of how powerful they were. The God of Darkness ruled over his own kingdom called Cielo, while the God of Light ruled over a kingdom called Gehenna. While the God of Nothing did what he wanted because he didn't want to rule anyone. When the Gods we're going to leave and go back to the own domains in the universe they gave a gift to us humans called elements the elements gave a small portion of the human population powers over elements such as electricity, fire, and water. These powers were cast in wide in terms of abilities and they only grew wider with time. Around 10% of the population got these powers and they were called elementals at the time elementals didn't know what to do with there new found power so they used it to make life easier but eventually we weaponized this power wars could destroy continents. This power was hard to control so when people lost control the causalities were high on both sides of the war. Now the world could be thrown in to chaos with ease so every kingdom made a treaty " The elementals will now be trained before going to battle and be taught how to control there powers" with that a new institution was built called Elemental Academy where now elementals that would like to fight for there country enroll to control there powers.