The 4th Grader Demon Lord

In this chapter, we learn that the demon king is known to be cruel and ruthless, and that he has even executed a person for his crimes. The demon king explains that he is able to use his own body as a source of energy to create his own magic, which he calls "mana." He explains that the only people who can see the flames of his magic are those who have the ability to see them. He says that if the hero of the story finds out about his plan, it will defeat the purpose of his action.