Perhaps the kiss is a moment of impulse for Draco, who has been secretly attracted to Hermione's intelligence and courage all along. Hermione, on the other hand, is initially shocked but then realizes she has some feelings for Draco too. Their relationship could then develop as they try to find common ground between their different houses' values. They might start working together on a project in the library, away from the prying eyes of their classmates, and slowly build a deeper connection through their shared love for learning and magic.
The kiss could lead to a conflict within the wizarding world. Since Draco is from a traditional pure - blood family and Hermione is a Muggle - born witch, their relationship could be seen as a threat to the status quo. This might cause a stir among the pure - blood supremacists, and Draco could be forced to choose between his family's beliefs and his new - found feelings for Hermione. Meanwhile, Hermione might have to deal with the disappointment of some of her friends who believe she should stay away from someone with Draco's family background.
Well, perhaps Hermione decides to keep the pregnancy a secret from most people at first. She might focus on her studies or her work in the wizarding community while trying to figure out how to provide for the baby. Meanwhile, Draco could be off living his own life, but then something might happen that makes him realize his mistake, like seeing Hermione and the baby by chance and feeling remorse.
One possible plot could be that there is a magical rift that somehow connects the Naruto universe and the wizarding world. Hermione, being the curious and adventurous witch she is, stumbles through the rift and ends up in the Naruto world. Naruto, intrigued by this strange new girl, helps her out. As they spend time together, they start to understand each other's worlds and eventually develop feelings for each other, leading to a kiss.
Perhaps Draco and Lucius find Hermione after she's been attacked by some dark creatures. Lucius might be more interested in using her injury to his advantage in the wizarding politics. But Draco, who has always had a bit of a soft spot for Hermione's intelligence and bravery, secretly tries to nurse her back to health. As Hermione recovers, she manages to outwit Lucius and also makes Draco question his family's allegiance to the Dark Lord.
One possible reason could be a moment of intense emotion. Maybe Draco is frustrated with Hermione's success or her constant opposition to his ideas in the wizarding world. It could also be a misinterpretation of feelings. For example, he might actually have some hidden admiration for her but doesn't know how to express it in a positive way, so it comes out as this aggressive action. Another aspect could be related to the overarching plot of the fanfiction world. Perhaps there's a power struggle or a mystery that involves both of them, and this physical act is a turning point in the story.
Harry would probably be very suspicious. He has always seen Draco as a bit of a bully and an enemy. He might think that Draco is up to something and try to warn Hermione to be careful. Ron, being more hot - tempered, could be quite angry. He might not understand how Hermione could even be in a situation where Draco kisses her. He might even lash out at Draco without really thinking about it. Ginny, on the other hand, might be more open - minded. She could see that there might be more to the situation than meets the eye and encourage Hermione to figure out her feelings before making any rash decisions.
Perhaps Voldemort adopts Hermione with an ulterior motive at first, like using her intelligence to further his own dark plans. But as he spends time with her, he starts to develop a strange sort of paternal feeling. Hermione, on her part, could try to subtly change Voldemort's views. She might introduce him to the value of Muggle - born magic and the importance of equality, which could gradually make Voldemort question his own pure - blood supremacist ideology.
One possible plot development could be that Snape's claim over Hermione creates a great deal of conflict within the wizarding world. The Order of the Phoenix might see it as a threat or a strange alliance. Hermione herself could initially resist but then start to understand Snape's motives, which could be related to protecting her from a greater danger.
Well, perhaps Hermione discovers some dark secret of Draco's that she can use as evidence to frame him for a crime, leading to his incarceration in Azkaban. Maybe it has something to do with his family's past actions that she twists to make him look guilty.
One possible plot development is that Ron gets angry at first. He might suspect Draco of doing something malicious on purpose. But as he investigates, he realizes it was an accident. Then he works with Draco reluctantly to break the spell on Hermione.
Hermione herself would also develop. With the support of two former adversaries, she might gain more confidence in dealing with the pure - blood elite. She could learn to trust them and in turn, teach them things about the Muggle - born perspective. This triangular relationship could lead to all three characters growing in unexpected ways.