Well, it could be that Deku's depression stems from the pressure of living up to All Might's legacy. Todoroki, being observant, realizes this. He starts by leaving little notes of encouragement for Deku in his locker. Then, he arranges for a group of their friends to have a support session for Deku. As they all share their own fears and hopes, Deku feels less alone. And as Todoroki spends more one - on - one time with Deku, like cooking together or just sitting in silence, Deku slowly begins to open up and his depression lessens.
Todoroki can start by simply being there for Deku. Just sitting with him in silence when Deku doesn't feel like talking. It shows that he's not alone. Also, Todoroki can share his own struggles. Since he has his own complex family situation, he can relate to feeling down sometimes. This can make Deku feel that his problems are not unique and that it's okay to not be okay.
There's a fanfiction called 'The Weight of Greatness' where Deku's depression stems from the pressure of living up to All Might's legacy. It's a well - written piece that really explores his mental state. And then there's 'Deku's Descent' which takes a darker turn and shows how his depression can affect his relationships with his friends and family.
There's also 'Unexpected Affection'. In this fanfiction, the kiss between Deku and Todoroki occurs in a very tense and emotional situation, like after a big battle where they realize their true feelings for each other. The author does a great job of building up the anticipation before the kiss.
A great plot twist might be related to their relationships. While in each other's bodies, they could accidentally say or do things that affect their relationships with other characters. For instance, Todoroki in Deku's body could unknowingly say something to Ochaco that makes her misunderstand Deku's feelings. Also, they could find it difficult to interact with their families in the other's body. Deku might not know how to handle Todoroki's father in Todoroki's body, leading to some tense situations.
One possible plot reason could be envy. Maybe Todoroki, as a villain in this fanfiction, is envious of Deku's popularity and the support he gets from fans. So, he kidnaps Deku to take away that source of admiration from him. Another reason might be related to power. If Todoroki has turned villain, he could see Deku as a threat to his plans, and by kidnapping him, he aims to neutralize that threat.
One plot idea could be that Todoroki is kidnapped by a villain who wants to use his powerful quirk for their own evil plans. His friends then embark on a dangerous rescue mission. Another could be that it was a case of mistaken identity and Todoroki has to figure out how to escape while also dealing with the kidnappers' demands. Or perhaps Todoroki is kidnapped by a group who wants to study his unique genetic makeup related to his quirk.
One popular 'female Todoroki and Deku fanfiction' is 'The Path of Heroes'. It focuses on their adventures together in a unique AU (alternate universe). Another great one is 'Flames and Green Lightning' which delves deep into their relationship development as they face various challenges side by side. There's also 'A New Bond' that shows how they support each other in their quests to become great heroes.
One interesting plot could be their journey of building a family together. They might face challenges like how to balance their hero duties with family life. For example, they could struggle with taking care of a child while also being on call to save the city.
Perhaps Deku discovers a dark secret about the origin of quirks and decides that the world would be better off without them. So, he starts a villainous campaign to eradicate quirks. He could form an alliance with other outcasts who have been mistreated due to their lack of quirks or abnormal quirks.
Well, a great plot could involve Deku using his dragon quirk to explore a hidden realm full of dragon - like creatures. He could learn about the origin of his quirk there. Or perhaps his dragon quirk has different forms, like a water - breathing dragon form for when he's near water, and he has to master switching between forms in battles.