He might cry a lot. Deku is very emotional, and being cheated on would be a very painful experience for him. He could also get angry, which is rare for him, but this situation would be so unjust that he might not be able to hold it in. He'd probably start to question his self - worth too, thinking that there was something wrong with him that made his partner cheat.
In fanfiction, if Deku gets kidnapped, his friends from U.A. High would likely launch a rescue mission. Bakugo might be especially determined, as much as he tries to hide his concern. They would use their quirks in creative ways to track Deku down.
There's also 'Injured and Alone'. In this fanfiction, Deku gets hurt while on a solo mission. It delves deep into his thoughts as he tries to survive in a dangerous situation, all while being severely injured. It's a great read for those who like character - centric stories when the character is in a tough spot.
Well, in the fanfiction, Deku might get a new look that changes how others perceive him. Maybe his friends at U.A. High are really surprised by his new haircut and it could lead to some funny or heartwarming interactions.
Well, it's popular because it taps into real - life issues like bullying. Many readers can relate to Deku's experiences on some level. Also, it creates a sense of drama and tension. We as readers are rooting for Deku to come out on top, and the whole process of seeing him deal with the bullies and grow stronger is very engaging. Moreover, it gives fanfiction writers a chance to put their own spin on the character and his backstory, which is always exciting for the fandom.
In the 'deku gets turned into a child fanfiction', it could lead to some really interesting storylines. Maybe he would see the world in a whole new way, with the innocence of a child. His interactions with his mentors could become more like a child - adult relationship where they have to guide him more. Also, his enemies might underestimate him at first, which could create some unique battle scenarios.
One possible plot for this fanfiction could be that Deku is facing a powerful and unknown enemy that has the ability to nullify his powers. He's in a desperate situation when Kurogiri shows up. Kurogiri, for reasons unknown to Deku at first, uses his portal - creating abilities to rescue Deku. It could turn out that Kurogiri has a connection to Deku's past that he's not aware of. Maybe Kurogiri was once influenced by someone who saw the same kind of potential in Deku that he himself had when he was younger, and that's why he saved him.
His friends could use their various quirks to track him. For example, if there are characters with enhanced sense of smell or the ability to detect energy, they could start the search. Then, they would plan a strategic attack on the kidnappers' hideout.