It's popular because it shows a different side of their relationship. Instead of the usual animosity, we get to see Snape in a mentoring role. It's a fresh take on their dynamic.
Well, in some fanfictions, Snape trains Harry to master the art of non - verbal spells more effectively. This gives Harry an edge in duels. Also, there could be a plot where Snape trains Harry in the history of dark magic not to use it, but to better defend against those who do. It's a way of making Harry more well - rounded in his magical knowledge.
One plotline could be that Snape trains Harry to face a new dark wizard threat. Harry, under Snape's guidance, discovers new spells and techniques that are crucial for this battle. Along the way, their relationship gradually evolves from one of animosity to a grudging respect.
Harry's self - confidence could be both bolstered and challenged. On one hand, as he masters new skills under Snape's tutelage, he'll feel more capable. But Snape's critical nature might also make Harry doubt himself at times. This internal struggle could lead to Harry becoming more resilient in the face of self - doubt and more confident in his own abilities in the long run.
One great story could be 'The Unlikely Bond' where Snape discovers Hermione's hidden potential in a unique area of magic and begins to train her in secret. It has a lot of character development for both of them.
Another way Snape could comfort Harry is by standing up for him in certain situations. Maybe when other teachers or students are being unfair to Harry, Snape steps in and defends him. This act of protection can be a great source of comfort for Harry, as it shows that someone is on his side even if they have had a rocky relationship in the past.
There's 'Snape's Guidance for Hermione'. The plot is centered around Hermione's struggle with her identity as a Muggle - born witch and how Snape's training helps her not only in magic but also in finding her place in the wizarding world. It has a strong emotional core as we see Hermione's insecurities and how Snape, in his own gruff way, helps her overcome them. There are also sub - plots involving other Hogwarts characters and their reactions to Hermione's special training.
In some fanfictions, Snape might use his advanced knowledge of potions to brew a special healing elixir for Harry. He could also use his magic skills, like a complex spell specifically designed to mend Harry's wounds, whether they are physical or emotional.
Sure, the Harry Potter fandom is huge and full of creativity. Writers might come up with a story where Harry is Snape's master for various reasons. It could be due to a prophecy or a magical bond that no one expected. In this kind of fanfiction, we might see Snape having to follow Harry's orders, which would be a complete reversal of their normal relationship in the original series. This could lead to some very intense and dramatic storylines.
One possibility could be that in this fanfiction, Snape takes Harry for some sort of training or protection. Maybe Snape realizes that Harry is in greater danger than Dumbledore anticipates and decides to take matters into his own hands. He might take Harry to a secret location to teach him advanced magic or to keep him away from the prying eyes of Voldemort's followers.