Another interesting change could be Sirius introducing a new magical element or concept into the story. He might bring in a long - forgotten spell or a magical artifact that has the power to either help or harm the characters. This would not only change the plot but also force the other characters to adapt to this new aspect of their world.
Harry Potter would likely be one of the main characters affected. Sirius was his godfather, so any changes Sirius makes could have a huge impact on Harry's life, his understanding of his family, and his role in the wizarding world.
In some fanfiction, Ash might have a change in his Pokemon team composition. For example, he could catch a rare or legendary Pokemon earlier than in the original series. This can lead to different battle strategies and storylines. Another change could be in his personality. He might be more confident or more mature, which would affect his relationships with other characters like his friends and rivals.
One idea could be that time gets distorted in the Twilight universe, and vampires start losing their immortality in a strange time - loop scenario. It would be really interesting to see how they deal with the fear of mortality.
Another possibility is that Draco falls in love with a character from the opposing side. His love could be so strong that it overrides his loyalty to his original side, leading him to change. For example, if he falls for a Gryffindor, he might start to see things from their perspective and gradually shift his allegiance.
Maybe the Sith Order decides to change their ways. In the fanfiction, the Sith could start to question their age - old pursuit of power through domination. They might form an alliance with some Jedi who also see the flaws in their respective orders. Together, they create a new order that aims to govern the galaxy in a more just and equal way, with a new understanding of the Force that doesn't divide it into light and dark but rather sees it as a whole with different manifestations.
Another plot could involve Harry being influenced by a family connection he discovers to a Death Eater. This newfound relation makes him reevaluate his beliefs and he starts to see the Death Eaters as more than just pure evil. He might think that by joining them, he can reform them from the inside.
One interesting plot twist could be Tony going back in time and preventing the creation of Ultron. This would completely change the dynamic of the Avengers. Without Ultron, there would be no Sokovia Accords fallout at least not in the same way. Another could be Tony changing the events that led to the death of a certain Avenger. Maybe he stops Loki from killing Agent Coulson, which could have a ripple effect on how the team forms and functions.
One interesting aspect could be the different character developments. For example, a fanfiction might change Naruto's relationship with Sasuke in unexpected ways. Maybe they become closer friends earlier or have a more complex rivalry.
In Naruto fanfiction, small changes can lead to big differences. For example, a small change in a character's backstory, like Naruto having a different mentor in his early days. This could affect how he learns jutsu and his overall development. Another small change could be in the way the Chunin Exams are structured, leading to different battles and alliances among the genin.
One common change is that he becomes moodier. The loss of Sirius is a huge blow, and he may swing between being extremely sad and angry. Another change could be that he is less likely to take risks without thinking. Sirius' death makes him more cautious as he realizes the consequences of recklessness.