Friendship is a very common theme. Given their different backgrounds and personalities, seeing how they become friends and support each other is often explored. For example, female Todoroki may come from a more troubled family situation compared to the optimistic female Deku, and their friendship can be a source of healing for both.
Overcoming differences is also prevalent. Their different power sets, personalities, and social standings are all differences that need to be overcome. This can lead to interesting plotlines where they have to learn to accept and work with each other, which in turn strengthens their relationship.
Common themes include the exploration of their individual insecurities. For female deku, it might be about not being strong enough at first, and for todoroki, his family issues. As they come together, they help each other deal with these. Also, the theme of finding a true connection in a world full of chaos is often there. Their relationship becomes a sort of haven in the midst of all the hero - related chaos. There's also the theme of acceptance, accepting each other's flaws and strengths.
A common theme is friendship. Since they are both characters in the same universe, many fanfictions explore how they become friends and support each other. Another theme is power combination. Their different quirks make for interesting scenarios where they team up and use their powers in creative ways. For example, Todoroki's ice and fire with Deku's One For All.
One common theme is possessiveness. Since Todoroki is yandere, he often wants to keep Deku all to himself. Another theme is the struggle between Deku's own agency and Todoroki's overbearing love. For example, Deku might want to pursue his hero career and have other friends, but Todoroki's yandere nature tries to limit that. Also, there's the theme of secrecy. Todoroki may try to hide his yandere tendencies from Deku and others at first.
Power imbalance is often a theme. Deku might gain new, more dangerous powers as a villain, and Todoroki has to figure out how to deal with that. There could also be a theme of trust. Since Deku is a villain, Todoroki has to decide whether to trust him or not. And if he does trust him, it could lead to all sorts of complications in the story.
One major theme is the idea of redemption and acceptance. Todoroki has issues with his father, and Deku has his own self - worth struggles. Fanfics often explore how they help each other accept themselves fully. Also, the theme of teamwork is prevalent. They work together in battles in the original story, and in fanfics, this teamwork can translate into a stronger emotional bond off the battlefield.
One common theme is friendship development. Since they are classmates and both aiming to be heroes, many fanfics explore how they become better friends. Another theme is mutual growth. They learn from each other's strengths and weaknesses, like Deku's spirit inspiring Todoroki and Todoroki's powerful quirk making Deku strive to improve more.
One common theme is self - discovery. As they travel through time, both Deku and Todoroki often learn more about themselves, their powers, and their true potential. For example, they might discover hidden aspects of their quirks.
One common theme is redemption. Bakugou, who was often a bully in the original story, has a chance to redeem himself in his relationship with female Deku. For example, in many fanfictions, he realizes his past mistakes and tries to make it up to her.
One common theme is the exploration of gender - how being female changes Deku's approach to Kacchan. For example, it might add a new layer of emotional vulnerability.
A common theme is probably the development of their relationship. It could start from friendship and gradually turn into something more romantic.