When a person reaches above S rank, his mana evolves into the world essence. The world essence is the higher form of energy and is much more powerful than the mana.
But by using concepts, people can increase the power of world essence even more.
For example, if a person is proficient with space element he can use his understanding of space element to turn world essence into conceptual energy of space.
Conceptual energise are the evolved version of world essence and not every person can turn world essence into conceptual energy.
Being at the disaster level, it is obvious that both Valtair and Malphasar had their own conceptual energies.
Valtair had a vague understanding of many different kinds of conceptual energies. But the main concept that he used in his world essence is the concept of destruction, making it the conceptual energy of destruction.
