If Ichigo joins the Shinigami Academy in fanfiction, his relationship with Rukia would change in an interesting way. They would no longer be in the situation where she is the more experienced one teaching him the basics. Instead, they could be classmates, and this could lead to a more equal footing in their relationship. He might also start to see other Shinigami in a different light, not just as powerful beings but as peers, which would change how he interacts with them all.
His relationships with his human friends might become a bit strained at first. He would be spending a lot of time at the academy, away from them. But with his new Shinigami friends, he would develop strong bonds. They would understand his new life and challenges better. For example, he might have a mentor - like relationship with an older student or a friendly rivalry with someone of equal strength.
Well, he might make some new and interesting friends. For example, he could meet other characters with unique powers and personalities. He would also have to learn all the rules and regulations of the Shinigami world, which could be quite a challenge for him as he's used to his own way of doing things. And of course, there would be a lot of training involved, which would help him become an even stronger Shinigami.
His relationship with Sasuke might change. Sasuke might be more intrigued or even a bit jealous of Naruto's new power. Naruto could use the Shinigami eyes to better understand Sasuke's inner turmoil, which is often related to his own spiritual and emotional state.
His relationship with Sasuke would become more complex. Since they are from different villages now, there would be a new dynamic. Sasuke might see Naruto's move as a betrayal to Konoha at first. But Naruto's intention could be to bridge the gap between the two villages for Sasuke's sake too.
His relationship with his friends would be very interesting. For example, Orihime might be more worried about his Hollow side and try to help him keep it in check. Chad could see his Quincy power as a new way for them to fight together. And Uryu might have a complex relationship with Ichigo as he is now also part Quincy. As a Shinigami, Rukia would be there to guide him in the ways of the Soul Society while also being curious about his other powers.
Naruto's relationship with his sensei, like Kakashi, would change. Kakashi would be both proud and cautious. Proud because Naruto is getting stronger, but cautious as the Shinigami - related training is uncharted territory. His bond with the other villagers would also shift. Some might see him as a protector with new, otherworldly powers, while others might be suspicious of the Shinigami's influence on him. Overall, his relationships would be in a state of flux as he adapts to his new self after the training.
Her relationship with her family could also be different. Her parents might treat her more delicately or have different expectations. And her siblings might tease her in new ways or be more protective. Also, her relationship with her enemies could change as they might underestimate her or be more hesitant to fight a girl.
His friends might be a bit wary of him at first. Since the Shinigami is often associated with death, they could be a bit scared of his new powers. But over time, they would probably come to accept it and see how he uses it for good.
His relationships would become more complex. He'd have to start from scratch with new people. Some might be friendly right away, while others could be hostile.
His relationship with Annabeth would become more complicated. Long - distance and the difference between the two camps could put a strain on their relationship. Among the Romans, he might develop a close friendship with some of the more battle - hungry demigods who admire his skills. He could also have a rocky start with the Roman leaders who may be cautious about his motives.
His relationship with Rukia would be different. Rukia might be more protective of Ichigo in her new form, seeing her as more vulnerable. And with Uryu, he might be more hesitant to interact with Ichigo as a female hollow at first, due to his Quincy beliefs.