The Hogwarts ghosts could potentially be involved. They see a lot that goes on in the castle and might witness Snape delivering the letter. The Bloody Baron, for example, could report this strange event to other faculty members or even try to interfere. Also, Voldemort or his Death Eaters might be indirectly involved if Snape's actions are part of a bigger plot against them or if they suspect Snape of betraying them by getting involved with Harry's letter.
Ron could also be involved. He's Harry's best friend, and when he sees Snape delivering the letter to Harry, he might get protective and suspicious. He could confront Snape or try to persuade Harry not to trust Snape so easily. Additionally, the owls that are usually associated with letter delivery in the wizarding world might play a role. Maybe there's something special about the owl that Snape uses to deliver the letter.
Dumbledore could be involved. He often has his fingers in many pies at Hogwarts, so he might be the one who arranges for Snape to deliver the letter to Harry for some greater good or part of his grand plan. Another possible character could be Hermione. She might notice something strange about Snape delivering the letter and start to investigate, suspecting that there's more to it than meets the eye.
Well, in this fanfiction, Snape might be forced by some magical circumstances to deliver Harry's letter. Maybe Dumbledore has a secret plan and Snape is reluctantly following it. It could lead to some interesting interactions between Snape and Harry, perhaps Snape finally shows a bit of kindness that Harry never expected from him.
The letter might be a summons to a secret wizarding council. Harry Snape's journey to deliver it could involve him facing his own inner demons as well as external obstacles. He might have to pass through dangerous terrains and encounter magical beings that are either trying to stop him or help him depending on their own agendas. As he gets closer to his destination, he discovers more about the true nature of the council and his role in the wizarding world.
It could be Voldemort. Even though he doesn't directly appear in the act of letter - delivering, his influence might be hovering over Snape. Snape might be worried that by delivering the letter, he's bringing another potential threat to Voldemort, and Voldemort's shadowy presence could create conflict for Snape.
Dumbledore can also be a significant character. He might be the one who arranges for Snape to teach Harry, having some grand plan in mind. He could be observing from the sidelines, guiding Snape's actions and Harry's progress subtly.
Maybe Snape has some complex emotions while delivering the letter. He might be secretly hoping Harry won't come to Hogwarts because of his dislike for James Potter, yet he has to follow Dumbledore's instructions.
Luna Lovegood might be in the fanfiction. She has a unique perspective on magic, and she could offer some interesting insights during the examination. Neville Longbottom could also be present. He's been through a lot in the wizarding world, and his presence could add another layer to the story. Additionally, some fanfictions might include characters from Snape's past, like Lily Potter. Her presence, either in flashbacks or in some magical form, could greatly affect the dynamic between Snape and Harry during the examination.
Hermione could be involved. She might be the one who tries to stop Harry from running and encourages him to face Snape. Or she could be the one who helps Harry to hide from Snape, using her intelligence and knowledge of spells. Ron is also a likely character to be involved. He might be with Harry when he starts running and together they try to figure out what to do about Snape.
One challenge could be Harry's distrust. Harry has had a long - standing enmity with Snape, so he might be reluctant to accept Snape's help. Another is the complex nature of Harry's problems. Harry has faced so many traumas and has a big destiny to fulfill. Snape might find it difficult to address all these issues without overstepping boundaries or causing more harm.
Snape might become more empathetic. After seeing Harry's memories, he could understand the pain and pressure Harry has been under. This new understanding might make him more protective of Harry in some way.
Perhaps Snape has a moment of softness. He sees Harry as an innocent child about to embark on a great adventure. His own past experiences with Hogwarts make him want to be part of this important moment for Harry, despite his usual cold exterior towards the boy.