Elementals Class

There is only 2 elementalist that can control all elements including lower class of elements. They are called the light wielder elementalist and the dark wielder elementalist. In the past the 2 elementalist who became the light and dark wielder elementalist they said that those 2 fighted for who is the greater and have more power.

There is a 5 element and many more lower class of elements in the world of Elements.
The highest 5 element are Fire,Water,Air,Earth,Lightning and the other is just lower class of element.
Each of the highest element has a 1 big country and in the center of it a school for all elements even for the lower class of element the school name is
Neutral Element School.

But what is the K-pop group EXO connection in here.