Harry could use his love for his friends and family. The power of love has been shown to be strong against Voldemort in the original series. So, when facing the Boggart - Voldemort, he could focus on the love he has for Hermione, Ron, and the rest of his friends, and this positive emotion could transform the Boggart into something less terrifying.
A simple plot idea is that the Boggart - Voldemort becomes so powerful in its manifestation that it starts to physically interact with the real world. Harry has to figure out how to stop it before it causes real damage. Another idea is that the Boggart - Voldemort begins to target Harry's friends one by one, using their worst fears against them. Harry then has to find the strength to face his own Boggart - Voldemort to save his friends. Also, what if the Boggart - Voldemort was actually being controlled by a new, hidden enemy? Harry would have to uncover this mystery while also dealing with his fear of the Dark Lord.
One possible scenario in this fanfiction could be that Harry Potter and Sasuke are somehow transported to a shared magical realm. When they encounter a Boggart, Harry might see Voldemort at first, given his past traumas. Sasuke, on the other hand, could see Itachi. But as they realize they are in this together, they combine their magical and ninja skills to defeat the Boggart. Maybe Harry uses a Patronus charm while Sasuke uses his Sharingan to disorient the Boggart.
A common boggart scenario in fanfiction is related to the characters' insecurities. For Harry, it could be that the boggart shows him as the cause of all his friends' misfortunes, emphasizing his fear of being a burden or a danger to those he loves. This can add more depth to his character and explore his self - doubts further.
It's possible. In the realm of fanfiction, the imagination knows no bounds. Writers might come up with such a scenario for various reasons, perhaps to explore a different side of the characters' relationships. But it's not a common or mainstream concept within the Harry Potter fanfiction community, as it goes against the typical character dynamics we expect from the series.
In many fanfictions, Harry Potter squinting at Voldemort could be a sign of intense focus. It might be that Harry is trying to read Voldemort's next move, or perhaps he's looking for some sign of weakness. For example, in some stories, Harry's squinting could be related to his newfound magical abilities that he's using to analyze Voldemort's magic signature.
In this fanfiction, it could be that Voldemort has a premonition. He sees that if Harry Potter dies, it will lead to a series of disasters that will also destroy his own plans. So, in order to preserve the balance or to keep his long - term goals intact, he saves Harry. For example, if Harry's death causes an uncontrollable chaos in the wizarding world, Voldemort's rule over the dark forces might be disrupted. So he steps in to save Harry.
In a story where Harry is raised by a boggart, he could have a very distorted view of the world. The boggart, not being a normal caregiver, might not be able to provide the love and stability that a normal family would. So, Harry might be more withdrawn and distrustful. He might also have a hard time making friends at Hogwarts as his upbringing by a boggart could have made him seem strange to other students.
Perhaps in the fanfiction, there is a magical tournament where both Harry and Sasuke are participants. One of the challenges involves facing a Boggart. Harry's fear of losing his wand (which is like his life in the wizarding world) and Sasuke's fear of losing his eyesight (since his Sharingan is so crucial) are what the Boggart targets. They initially struggle as they are used to fighting their battles alone. But as the Boggart gets stronger, they realize they need to work together. Harry uses spells to distract the Boggart while Sasuke uses his ninja speed to get behind it and deliver a final blow.
The wizarding world might be in shock. People who have always seen Voldemort as the ultimate evil would be confused. They would have to re - evaluate their views on Voldemort. Harry, on the other hand, would be in a very strange situation. He might be distrusted by some of his friends who think he has made a deal with Voldemort.