One possible plotline could be that after facing a great betrayal, Harry decides to close himself off emotionally and focus solely on becoming stronger in magic. He might train in isolation, away from his friends, and develop new and powerful spells.
Perhaps Harry witnesses the death of a loved one due to his own weakness. This could drive him to become cold and strong. He could then start to take more risks in battles, using his newfound cold - heartedness to his advantage, not hesitating to use dangerous or dark magic if it means achieving victory.
One possible plotline could be that Harry discovers a hidden pirate ship in the Forbidden Forest. He then decides to join the crew and learns the ways of piracy. Another could be that he is magically transported to a pirate world and has to adapt to survive as a pirate.
The Ministry of Magic could turn into an antagonist. If Harry's new cold and strong ways are seen as a threat or too radical, they might try to stop him. This could lead to a conflict between Harry and the wizarding government.
One event could be the loss of a very important person in his life. This loss could shatter his previous beliefs and make him think that being soft and warm - hearted was a weakness. He might also have been exposed to a group of people who took advantage of his kindness. As a result, he decided to toughen up and become cold. Also, perhaps he went through a series of difficult battles where his lack of strength nearly cost him his life, so he trained hard to become strong and in the process, became cold as a defense mechanism.
In a 'fem Harry becomes a Goa'uld fanfiction', it could start with fem Harry already having some knowledge of the Goa'uld from her studies in the wizarding world. When she actually encounters them, she tries to use her knowledge of magic and the Goa'uld's weaknesses to her advantage. She might form alliances with some of the human resistance groups in the Stargate universe and together they fight against the Goa'uld domination. There could be a lot of character development as she adapts to this new and dangerous world, and her relationships with the people she meets would also be an important part of the plot.
A plotline could involve Hermione being magically influenced by a charm that is meant to be a joke but goes wrong. As she becomes more like a 'bimbo', she starts to interact with her friends in different ways. Ron might be initially confused and Harry could be worried. But as the story progresses, Hermione uses her new - found different perspective to solve a mystery in Hogwarts that no one else could because she looks at things from an unexpected angle.
One possible plotline could be that Ash is betrayed by his friends. This heartbreak and sense of abandonment turns him evil. He then starts using his Pokémon in cruel ways to seek revenge on those who wronged him.
One possible plotline could be that Naruto discovers a hidden jutsu or artifact that grants him immortality. He then has to deal with the consequences of living forever, like seeing his friends and loved ones age and die while he remains the same. Another could be that an enemy tries to steal his immortality, leading to a great battle.
One possible plotline could be Izuku adjusting to her new gender identity while still trying to pursue her dream of being a hero. She might face different challenges and prejudices in a male - dominated hero world as a girl. For example, some male characters might underestimate her at first but she proves them wrong with her skills and determination.
One possible plotline could be that Naruto is somehow transported to a world where sorcery is the main power source. He then has to learn to become a sorceress to survive and find his way back home.
Well, in some 'harry becomes lord fanfiction', he could be given a lordship over an ancient wizarding family's estate. Then he discovers hidden secrets about the family, like a long - lost magic or a prophecy. He may also have to face challenges from dark wizards who want to use his new position for their evil plans. He has to quickly learn about politics and power plays in the wizarding society.