Well, one possible plot could be that Deku gets hit by a villain's quirk during a battle. This quirk erases his memory. His friends, like Uraraka and Iida, then try to help him remember who he is. They might show him his hero notebook, hoping it jogs his memory about his dream of becoming a great hero.
It could be a new villain who has the power to manipulate memories. This villain might target Deku specifically because he sees Deku as a threat to his plans. He wants to erase Deku's memory so that he can't interfere with his evil schemes in the hero world.
A 'Naruto loses his memory fanfiction' might involve a mysterious curse placed on Naruto. He forgets not only his personal relationships but also his ninja skills. His sensei, Kakashi, could take it upon himself to reteach Naruto everything from the basics. Meanwhile, Naruto might form new, unexpected relationships with people in the village who don't know the 'old' him, and these new relationships could either help or hinder his journey to regain his memory.
Well, one possible plot could be that the crew has to deal with a new Luffy who doesn't remember them. They might have to re - introduce themselves and re - create their bonds. For example, Zoro could try to jog Luffy's memory by showing him his three - sword style, which was always something Luffy was impressed by. Maybe they go on a quest to find a way to restore his memory, facing new enemies along the way who are trying to take advantage of Luffy's weakened state.
In this fanfiction, perhaps Edward's memory loss is caused by a magical spell or an accident. As he tries to regain his memory, he stumbles upon a group of friends or allies who are also on a journey of their own. Together, they face various challenges and along the way, Edward slowly starts to remember fragments of his past, which could be both good and bad memories.
It could be Orochimaru. He's always been interested in Naruto's power. Maybe he devises a plan to make Naruto lose his memory so he can manipulate him more easily, perhaps to use him as a weapon against the Hidden Leaf.
It could be a marine admiral who has developed a new weapon that not only causes physical harm but also memory loss. This admiral might see Luffy as a big threat and decides to use this weapon on him to weaken the Straw Hat crew.
Maybe Orochimaru manages to get his hands on Naruto and subjects him to some dark and twisted experiments. These experiments could mess with Naruto's mind, causing him to lose his sanity. He could start seeing illusions all the time, believing his friends are his enemies. As a result, he'd be in a constant state of confusion and aggression, and his once - positive attitude towards life and ninja - hood would be completely gone.
In 'Harry Loses His Emotions Fanfiction', it could be that Harry experiences a really traumatic event. Maybe he witnesses the death of a very close friend in a battle. This shock is so great that it makes him shut down his emotions as a self - defense mechanism. He then becomes cold and distant, and the story could be about how his friends struggle to reach the old Harry again and help him heal.
Maybe in the fanfiction, Harry's twin could be lost in a magical accident. For example, during a wizarding battle, the chaos causes them to be separated, and Harry spends the rest of the story trying to find his twin.
In such a fanfiction, perhaps Naruto could be wrongly accused of something that leads to him being stripped of his birthright. Maybe a false claim about his connection to the Nine - Tails is used against him.