In an AU travel fanfiction, Izuku might have an adventure in a world ruled by a strict and oppressive regime. He would have to find a way to inspire the people there to rise up against the tyranny without using excessive force. He could also travel to a world where quirks are not the main form of power, but instead, it's a world of magic and sorcery. Here, he would need to learn new skills and adapt to a completely different power system. Additionally, he could end up in a world that is constantly in a state of flux, with landscapes and rules changing randomly, and he has to be constantly on his toes to survive and help those in need.
It is indeed interesting. The idea of Izuku in an AU travel fanfiction opens up a whole new realm of possibilities. It could involve him traveling to different time periods in the 'My Hero Academia' universe or even to entirely different fictional universes. This can lead to exciting crossovers. Imagine Izuku meeting characters from other popular anime or manga. The contrast between his worldviews and those of new characters he meets can create engaging story arcs, full of drama, humor, and self - discovery.
Izuku would probably be terrified at first. After all, he's been kidnapped by villains. But then, his hero - like determination would kick in. He might start looking for ways to escape or at least resist their plans.
All Might would be furious. He would see it as his failure to protect Izuku. He would probably mobilize all the resources he has, both in his hero form and his connections in the hero world, to rescue Izuku. And he would be blaming himself all the while for not being there when Izuku was kidnapped.
If the grandfather is very warm and accepting, Shikaneji would feel relieved and happy. They might open up more about their relationship and their dreams. Nejire could start chatting excitedly about their future together, and Shinsou would relax and join in the conversation more. However, if the grandfather is not so friendly, they would be disappointed and perhaps a bit defensive.
Some characters might be immediately terrified. They could avoid Izuku or even try to drive him away. For example, classmates who don't understand his quirk might spread rumors about him.
Eventually, he might come to accept it in a grudging way. If Izuku is wearing the clothes for a good reason, like in a team - up situation where it's part of a strategy, Bakugou might tolerate it. But he'll still probably make some snarky comments about how Izuku better not ruin his clothes.
All Might would probably be very supportive. He's always been about the spirit of heroism, not gender. He'd encourage Izuku (as a girl) to keep training hard. Bakugo might initially be shocked and then try to act all tough, but deep down he might be a bit confused about his feelings towards her. Ochaco would be excited to have another girl around and might become even closer friends with Izuku.
Some in 1A might be in awe. For example, if Izuku has a particularly powerful or unique quirk in fanfiction, characters like Mineta might be jealous. He often shows envy towards those with strong abilities.