Well, their friendship could potentially change Sasuke's path. Since Sakura is friends with Itachi, she might be able to communicate better with Sasuke about his brother. For example, she could tell Sasuke about the good side of Itachi that he never knew, which could make Sasuke less vengeful and more focused on rebuilding his clan. This would be a huge shift from the original storyline where Sasuke is mainly driven by revenge against Itachi.
A possible plotline could be that they made a childhood promise to always protect each other's families. When Itachi is faced with the decision to kill his clan, Sakura tries to stop him, not fully understanding the situation at first. This creates a rift between them, but later, as Sakura learns the truth, she tries to help Itachi in her own way, like protecting Sasuke from the shadows as Itachi had asked her to in a moment of desperation.
In Itachi yaoi fanfiction, Itachi is often depicted as a complex and mysterious character. He is usually highly intelligent and powerful, which makes him an alluring figure in romantic or relationship - based stories. His loyalty, whether it be to his family, his village, or his love interest in the yaoi context, is also a common characteristic explored.
He would likely be adapted as a very powerful and mysterious character. His skills in the Naruto universe would translate into some sort of special magical abilities in the Harry Potter world. For example, his Sharingan could be like a super - powerful magical eye that gives him unique insights.
Sasuke is often paired with Itachi in these fanfictions. Since they are brothers, when Itachi time - travels, his interactions with Sasuke are crucial. Sasuke might be at a different stage in his life, and Itachi could try to influence his development. Another common character is Naruto. Naruto's ideals of friendship and peace could contrast with Itachi's more complex and tragic view. Their interactions could lead to interesting plot developments.
Sasuke is often paired with Itachi in these fanfictions. Their complex relationship from the original Naruto series can be explored in new ways in another world. For example, they might be on a mission together in a world full of unknown dangers. Another popular character to be paired with Itachi is Naruto. Their different outlooks on life and friendship can create interesting dynamics, especially when they are in a strange new world where they have to rely on each other more than ever. Shisui could also be paired with Itachi. Since they were friends in the original story, in the fanfiction, they could be reunited in another world and face challenges together, perhaps against a new and powerful enemy.
Well, there might be characters from their clan. Since Itachi is from the Uchiha clan, other Uchiha members could play significant roles. They could be elders or other young Uchiha who are involved in the clan's affairs and in turn, affect Itachi and Izumi's story.
Itachi would probably be very calm and composed. He might see Sarada as a symbol of the new generation of ninjas in the village. He could be gentle with her, perhaps sensing her potential and her desire to grow as a ninja.
He could also develop through facing new threats in the RWBY world. The Grimm are different from his usual opponents in Naruto. Dealing with them might force him to adapt his combat style and in turn, grow as a character. For instance, he might have to rely more on others' skills in a team - based RWBY battle scenario.
One reason could be that he sees something special in Sakura. Maybe he admires her strength or her kind heart, and he doesn't want to lose her to someone else who might not appreciate her as much as he does.