He might start to rely more on his own instincts. Without his friends around, he would have to make decisions all by himself. For example, when facing the challenges related to the Triwizard Tournament, he would need to figure out strategies alone, which could lead to some very different outcomes compared to the original story.
When left alone in his 4th year in the fanfic, Harry's character would experience a significant shift. He would be forced to face his insecurities head - on. This could make him more confident in the end as he overcomes them. He may also develop a different relationship with his professors as he has to seek their help more directly without his friends to act as intermediaries. His social skills might also change as he has to interact with other students in a new way, since he no longer has his usual group to rely on.
One thing that could occur in the 'Harry Potter 4th Summer Fanfic' is that Harry is being trained by some of the older students or even a teacher in secret. This training could be related to combat skills or ways to deal with dark magic. He might also be researching about the history of the Triwizard Tournament in the library at Hogwarts, which he has sneaked into. He could discover some dark secrets about the tournament's past that might put him in a better position to face the challenges ahead.
Well, he might be able to change some of the bad things that happened. Maybe he could stop Umbridge from being so cruel. He could also be better prepared for the challenges that year brought, like the fight against Voldemort's forces.
Well, in the 5th year trial fanfiction, Harry might face some unjust accusations. Maybe the Ministry of Magic is trying to pin something on him again, just like in the original story. He could be put on trial for using magic outside of school when he was actually defending himself.
In this fanfic, Draco could also provide Harry with some inside knowledge about the Ministry of Magic. Given his family's connections, he might know about certain underhanded dealings or weaknesses in the Ministry that Harry could use to his advantage in his fight against the Dark forces. For instance, Draco could tell Harry about a secret entrance to the Ministry that could be used for a stealthy mission.
He might face numerous terrifying monsters. Tartarus is full of dangerous creatures in the fanfic world, and Percy would have to fight for his survival all by himself.
Maybe he's frustrated with all the prophecies and his role in the fight against Voldemort. He doesn't want to be constantly pushed into being the hero. He might want some time to figure out who he really is outside of all these expectations. Also, he could be feeling a bit overwhelmed with his studies and the extra - curricular activities like being in Dumbledore's Army. All these things together make him long for some solitude.
In fanfic, when Harry Potter goes to Gringotts, he might discover some long - lost secrets about his family's vault. There could be hidden spells or artifacts that were left there by his parents or ancestors.
The fangirl could be in for a real treat. She may discover unique interpretations of the Harry Potter universe. Fanfics often explore different character backstories or alternative timelines. So, she could learn about what would have happened if Harry had been sorted into Slytherin instead of Gryffindor. She might also encounter new magical creatures or spells that the author of the fanfic has created. And, depending on the type of fanfic, she could be part of a big adventure to save Hogwarts from a new, even more powerful dark wizard than Voldemort.
Well, it could be that Harry and Ginny have some really sweet moments during their 7th year in fanfic. They might have secret dates in hidden parts of Hogwarts, sharing their fears and hopes for the future while the war is raging on. And perhaps Ginny becomes an even stronger witch, standing side by side with Harry in a way that surprises everyone.