It could make Snape more bitter. Since he lost Lily to James, he might become even more withdrawn and focused on his own studies or other solitary pursuits. This could further isolate him from others and fuel his resentment towards James and his group.
On the other hand, it could also be a turning point for Snape's growth. Losing Lily to James might make him realize his own flaws, like his association with the wrong crowd or his lack of social skills. He could then start to work on himself, trying to become a better person in the hopes of winning Lily back, even if it's ultimately in vain.
It would strain their relationship even more. Snape's love for Lily was already on shaky ground due to their different paths. Seeing her with James would make him feel like she has completely chosen the other side, and he might start to resent her a bit.
Perhaps in the fanfiction, James is seen as more accepting of Lily's friends and her social circle. Snape, on the other hand, might be associated with a darker crowd or have some beliefs that Lily doesn't agree with. For example, if Snape is too involved with the Dark Arts in the fanfiction, it could be a turn - off for Lily.
Well, in some fanfictions, Snape's discipline makes Harry more determined. Harry, facing Snape's strictness, learns to be more cautious in his actions and words. It forces him to think twice before doing something, which in turn helps him grow into a more responsible wizard.
The abuse in fanfiction can make Snape more complex. It can lead to him being more withdrawn and bitter, which in turn affects how he interacts with others. For example, he might be even more hostile towards Harry Potter if he has endured extra abuse in the fan - story.
Snape's view of James might not change much at first. He has such deep - seated hatred for James due to their past. But if the fanfiction shows James in a more positive or sympathetic light, he may start to question his long - held beliefs about him, just a little bit.
If Snape walks in on Lily and James in fanfiction, his character could develop in a more bitter and vengeful way. The sight of Lily with James would be like a dagger to his heart, and he might be driven further towards the dark side. He could start to plot more maliciously against James, using his skills in potions and dark magic to his advantage.
It might also influence the way the animals in Animalia interact with Snape. If they sense his deep and unrequited love, they could either be sympathetic or try to play matchmaker in a magical way. For example, a group of fairies could try to bring Lily's spirit closer to Snape through their magic.
It can intensify the conflict. Snape's jealousy can lead to more confrontations between him and James, which might draw in their respective friends and create more chaos at Hogwarts.
Snape might be initially in shock. He had trusted Lily deeply, so the betrayal would hit him hard. He could become very angry and bitter, perhaps vowing revenge against her. He might also close himself off emotionally, not wanting to trust anyone again.
Harry's character development would be significantly different. With his parents alive, he would be exposed to a more stable family environment. His magical education could start earlier and be more comprehensive as he learns from two powerful wizards. This could make him more powerful and less impulsive. Instead of seeking validation from others like he did at Hogwarts in the original story, he would have the unconditional love of his parents, which could shape him into a more well - rounded and less angst - ridden character. For example, he might not have had such a strong urge to prove himself in dangerous situations.