The issue I want to address is the consistency of using
this calc for rating 5% Izuku's AP.
Shattering the steel beam into pieces is only a City Block level portion of the feat. What makes this calc Multi-City Block level is the assumption that Izuku heated up the entire
536.579 cubic meters of steel up by
825°C using only the kinetic energy of his kick.
That's a pretty substantial transfer of energy. He's just seemingly performing a typical 5% kick and he imbued a volume of steel that big with Multi-City Block levels of thermal energy?
Does this level of energy exchange happen anywhere else in the manga?
I went back over the manga and looked at an assortment of 5% and 8% Izuku's feats when he interacts with objects instead of people.
1)
Smashes a sofa into the air while training with Gran Torino.
2)
Smashes a collection of knifes apart with his kick.
3)
Kicks a boulder of cement apart.
4)
Kicks a section of ground.
5) Kicking multiple walls to pieces
here,
here,
here, and
here.
When Izuku interacts with environment, nowhere is it suggested that the majority of the energy he's inflicting with his blows is thermal energy. He is not significantly raising the temperature of anything in any of the scenes. He's not super-heating any of Spinner's knives, or heating up the cement and bricks in the walls he kicks (which due to their lower density and smaller volume would require even less energy than the movie calc in order to be heated up to the same degree despite a higher specific heat capacity for the materials).
So why do we have this one scene where Izuku is heating up a large mass of steel by 825°C and nowhere in the manga does he do the same thing?
Well, one explanation which I think people generally don't like is that Izuku "heating up the steel" as he fragments it is just a flair of the movie. An animation effect to exaggerate the feat or without putting much thought into the physics involved. Like how objects can seemingly shatter neatly into perfect cubes as bizarre as that is.
Is this a likely explanation?
Well, yes, I think it is. As we all know, animation can be prone to exaggeration.
Take the scene of Deku's and Shotos' final clash from the Sports Festival arc. In the manga,
Deku and Shoto are at best a few meters away from each other prior to their final clash.
In the anime,
you'd be forgiven for thinking that Deku leapt damn near a hundred meters to reach Shoto judging by how far the distance between them suddenly became.
Not to mention that in the manga
the walls that Cementoss makes are not that much largers than Deku and Shoto, and don't shatter into as much rubble - whereas in the anime
the insanely huge amount of rubble created should be all means be land in the the crowd and killing hundreds from how many flying pieces of debris is created.
I'm aware we don't have a manga version of the scene in the film to directly compare it to 1 to 1, but what we do have is all of Izuku's other 5% feats listed further up. I'm not comparing the level of destruction he's causing so this does not fall under the AoE fallacy. The Multi-City Block level rating is coming from the effects of Izuku's own attacks on the environment so I'm paying attention specifically to the effects of Izuku's attacks on the environment. That can't be both relevant and irrelevant at the same time.
I'm not objecting to Izuku being Multi-City Block level via some other way, but the method used here does not seem to be representative of Izuku's actual capabilities as it is an inconsistency.
