And that's where it falls apart. Medea for example is a magister from ancient times, and enemy caster is exactly like that. Becoming a hero allows people to break physical laws, and or make reality not matter. Its not a matter of it being a fireball. Its a fireball because it was suddenly, and unexpectedly pulled out of the air by way of non combustion, usually, and them just flinging it at them. It would require me to make up explanations of why things work when I don't have those answers because anime/comic book logic.