Now if you look at Shoto, Endeavor, Tetsutetsu, or any character who has resistance to fire/cold in this verse.
You'll usually see a rating in their durability that says Blank level against Ice/Cold/Fire/Heat attack. As a way of showing their resistance towards certain level of attacks. This seems to make sense at a glance.
However this is wrong, as this rating doesn't actually tell us how heat resistant someone is. Let me explain. Damage caused via heat/cold happens because of extreme temperature. High temperature burns/melt and low temperature freezes. The energy that it takes to produce that heat/cold doesn't translate into temperature automatically.
Obviously higher/lower temperature would give off more energy. However size/volume is a major factor here as well.
Example: Character A can produce fire that can instantly melt through steel. Character B can produce a fire that can't melt steel, but can melt copper. In this case Character A's fire is superior correct? They can melt things Character B's fire cannot melt, as it has a higher temperature.
However Character B's fire is calculated at
High 8-C levels of energy, while Character A's fire is only
9-A. People who tank Character B's fire are given High 8-C durability towards fire attacks, while Character A's fire is only 9-A. This implies that Character A's fire cannot harm those who can tank Character B's fire.
This is incorrect. As heat/cold damages via extreme temperature, the more extreme temperature will do more damage. Character B's fire has a higher rating because the area that fire covers is greater than what Character A's fire can cover.
Yes Character B's fire does require more energy to create, however it isn't because it's hotter, it's because it's bigger. The flame are still incapable of melting steel, while Character A's flame can melt those things.
High heat can cause damage physically by a small amount, however this has nothing to do with what I'm talking about. I'm talking about heat/cold resistance only. Which is currently labeled on the MHA profiles as, in Shoto's case,
Town level/
Mountain level+ against Ice/Fire Attacks. What does this rating mean? It means nothing.
The rating is pointless as this doesn't tell me how hot or cold the flames or ice Todoroki resist is. What if Todoroki fights someone who's fire was calculated at 8-A, but has a temperature of ten thousand degrees Celsius? Does Todoroki tank his fire or does he get roasted? I'm pretty sure anyone you'd ask would say he gets roasted.
Todoroki is incapable of attacking with the energy he uses to create that fire and ice. And as discussed, the rating given is irrelevant. Todoroki's flames/ice being 7-C or 7-A doesn't change the fact he can't burn/freeze anyone who can resist temperatures greater than his own. There is no universal energy source either, Todoroki cannot put the energy he uses to create his flames/ice into anything else.