How Does Todoroki X Yn Fanfiction Develop Emotional Character Growth?

I feel like the strength in Todoroki/YN fics often comes from that initial distance his character starts with. He's so closed off, wound so tight, and has this huge, complicated history with his family that he doesn't even know how to talk about. A writer can build emotional depth by having the YN character notice the small things—not just the scar, but maybe how he tenses when someone raises their voice too loud, or the way he always defaults to using his ice side for mundane tasks, like it's a reflex he can't break. The emotional work is getting him to a point where he chooses to use his fire around the YN, not because he has to, but because he wants to share that part of himself. The development can't be rushed, though. A lot of fics mess up by having him spill his entire traumatic backstory in chapter two. Real depth comes from awkward silences that gradually become comfortable, from him learning how to accept a compliment without freezing up, and from the YN character having their own life and struggles that he, in turn, learns to support. It's a two-way street. Maybe the YN has a quirk they're insecure about, or family stuff of their own, and seeing Shouto navigate that gives him a new perspective on his own issues. The best fics make me believe he's learning how to be a person, not just a hero or a product of Endeavor's design, and the relationship is the catalyst for that. I've read some where the emotional climax isn't even a big confession scene; it's something like him bringing two cups of tea, one slightly cooler because he used his quirk to get it to the exact temperature he remembers the YN likes. That kind of quiet, observed detail hits harder than any dramatic 'I love you' shouted during a fight, at least for me. It shows he's paying attention, he's learning care, and he's using the very power that was a source of pain to do something gentle for someone else.