So part 2 of the fight is mostly about Toya. It’s about this kid who inherited an iron will and will not be put down by a power that he’s told he can never match. So Toya fights back. He copies Shoto’s Phosphor (but his expression of it is still pure destruction) and he goes to recreate Sekoto peak to force Enji to look at him. He finally makes his father to stop running away and properly look at the tragic monster he created.

And the family that changed rushes in to save him and even if his needs are fulfilled for a single moment (paralleling Toga’s smile), it’s not enough. It’s too little, too late. The family can’t calm down Touya and Touya can’t stop himself because he never learnt how to turn off the fire.

So Shouto is still very much the hero they need to save them, he’s the last piece of the puzzle, he’s the one who can arrive aided by the friends he made and use his power to save everyone.

I read the second fight as the accumulated trauma in the family (fire) vs the power of everyone’s healing (where still the main source is Shoto) represented by ice.

But I think the key turning point here is that Touya doesn’t want to continue fighting anymore. He wants to talk. He wants to pour out his rage and anger, but he doesn’t want to burn the world down anymore. And that’s because both his psychological need of being seen and physical need of turning down the flames are met. It’s a low point, but I think it’s one you can build on.