Writers often develop Snape's character in married fanfictions by showing his vulnerable side. Since he was a rather closed - off character in the original series, in fanfictions about his marriage, they might show him opening up to his partner. For example, he may share his fears about his past actions and how he's worried about being truly loved.
In some fanfictions, Severus Snape's character develops by becoming more open - minded towards Muggles. He might start off with his typical wizarding - world prejudices, but through various interactions, he begins to see Muggles in a new light. For example, he could meet a Muggle scientist whose thirst for knowledge reminds him of his own love for potions, and this changes his view.
Snape's character could become more complex. He might start to incorporate some of Merlin's wisdom into his own actions. For example, Merlin was known for his ability to see the good in people, and Snape could start to do the same. Instead of just being bitter and resentful towards Harry, he could start to see Harry as a potential ally in a greater fight, much like Merlin saw the potential in the young knights of Camelot.
Snape's character development in these fanfictions is quite interesting. At first, he might be helping Harry out of a sense of obligation to Lily. But as time goes on, he starts to form a unique bond with Harry. His interactions with Harry force him to confront his own prejudices and grudges. He becomes more empathetic towards Harry's situation, which is a big change from his initial coldness. For example, in some stories, he begins to understand Harry's loneliness and tries to offer some form of companionship, which is a huge step for a character like Snape.
Snape's character development in these stories can be quite extensive. He starts off as a somewhat cold and distant figure, but as he raises Harry, he begins to soften. He might start to show more humor, which is a side of him we rarely saw in the original books. He also becomes more forgiving. For example, he might forgive Harry for the small mistakes he makes as a child growing up. And his relationship with other Hogwarts staff may improve as they see the positive influence he has on Harry. Overall, his character goes from a solitary, bitter man to a more caring and involved member of the wizarding world.
In these fanfictions, Snape's character often develops from a seemingly cold and unfeeling person to someone with more depth. When he saves Harry, it starts to chip away at his facade. For example, he might initially save Harry out of obligation but as time goes on, he realizes he has a genuine care for the boy. This is different from his canon behavior where his feelings are mostly hidden.
Snape's character might develop more positively. Without the burden of his past mistakes and betrayals haunting him, he could be more confident. He might be more open to forming friendships, especially with Dumbledore. Their relationship could start on a more equal footing, leading to a more trusting bond.
Snape would likely become more confident in his place at Hogwarts. As the heir, he has a new - found sense of belonging that could soften his harsh exterior. He might be more open to helping students, especially those who show an interest in the history of Hogwarts.
In many of these fanfictions, Snape is often portrayed as a complex and misunderstood figure. He is shown as having a deep - seated sense of loyalty, whether it's to Hogwarts or to the memory of Lily. For example, in some stories, he acts as a sort of guiding spirit for Albus Severus, using his past experiences to help the young Potter navigate the challenges at school.
His character might develop more of a social side. As a bartender, he has to interact with various people, so he could become more approachable. For instance, he might start to crack a rare smile or two when chatting with regular customers.
Some writers might quit writing Severus Snape fanfiction because they run out of new ideas. After exploring many aspects of his character, such as his relationship with Lily or his role in the Hogwarts faculty, they may feel there's nothing fresh left to write about. Another reason could be lack of audience response. If they don't get enough feedback or reads on their stories, it can be demotivating.