She would change the story because she would be a target. Those who caused the massacre would want to finish the job. This would lead to many chase and escape scenes. Also, other characters would be divided in their opinions about her. Some would see her as a threat, while others would see her as a symbol of resistance.
She could survive by being away from the village during the massacre. When she returns, she is shocked. She decides to investigate the real cause of the massacre. Along the way, she discovers some dark secrets about her clan and the village. This knowledge gives her a new purpose, and she uses her Uchiha powers to bring the truth to light.
Her character might develop a sense of vulnerability. After surviving such harrowing experiences, she could start to question her own invincibility. This newfound vulnerability could make her more relatable to other characters and readers. She may also become more cautious in her actions, weighing the risks more carefully before jumping into combat.
If Jeice survives in Dragon Ball Z, it could have a huge impact on the story. For one, he could potentially reform and become an ally. Maybe he realizes the error of his ways after seeing the power of the good guys. He could then use his skills to help the Z - fighters in future battles against other threats. Another possibility is that he would hold a grudge and try to seek revenge on the ones who almost killed him. This could lead to new story arcs and battles.
Naruto's story would be drastically different. He would probably have a different goal in life. Instead of seeking the village's recognition as he originally did, he might be more focused on restoring the Uchiha clan's honor. His friends would also be different. He'd be closer to the remaining Uchiha members and might not form the same bonds with the people like Shikamaru or Choji. His ninja path would be more centered around the Uchiha's secrets and powers.
One way is to make the Otsutsuki OC a hidden observer during the Uchiha massacre. They could be there to study the Sharingan or the power dynamics within the Uchiha clan. For example, they might be interested in how the Uchiha's emotions, like hatred, are related to the power of their eyes. Another way is to have the OC be a factor that somehow influences Itachi's decision. Maybe they offer him a different option or some knowledge that makes him rethink his actions, but in the end, the massacre still occurs due to the complex web of political and clan - related reasons in the Naruto universe.
If Naruto were born an Uchiha, his relationship with Sakura might be affected. Sakura might be more drawn to him initially because of the allure of the Uchiha clan. However, Naruto might be more focused on restoring the Uchiha name and proving that they are not all bad. His relationship with the villagers would be complex. Some would be fearful, while others might hope that he could use his Uchiha powers for the good of the village.
If Sasuke Uchiha were in Game of Thrones, the power dynamics would shift drastically. His ninja skills would make him a formidable force. He could easily outmaneuver many of the characters in combat. For example, in the battles for the Iron Throne, his Sharingan ability to predict movements would give him an edge over swords - only warriors. Also, his brooding and mysterious nature might attract some characters while alienating others, much like in his own Naruto universe.
With Sasuke, he might show a more tender side. Usually aloof, he could become more protective and concerned for her well - being. Their relationship could shift from a competitive one to a more caring and cooperative one as he tries to help her get better.
Her relationships would be very different. For example, with Sasuke, instead of having the deep emotional bond filled with rivalry and a touch of friendship, it would be more of a cold - calculated relationship. She might see him as just another powerful ninja to measure herself against. With Sakura, instead of having a normal girl - friend type of relationship, Sakura might be constantly trying to figure out how to get through to her, while female Naruto just sees Sakura as someone who is useful for her medical skills during battles.
Well, the OC might try to prevent the Uchiha Massacre. Maybe they have a different view of the Uchiha compared to the Konoha leadership. They could try to convince the Uchiha to flee or negotiate with Konoha. If they have unique powers or knowledge, they could use it to expose the real motives behind the planned massacre and create a situation where the Uchiha are spared. This would completely rewrite the story of the Uchiha's downfall.