In some versions, Snape uses his knowledge of the Dark Arts and Hogwarts' secrets. He might set up a situation where Umbridge is lured into a restricted area of the castle and gets into trouble with some magical creature or ancient magic, causing her to be removed from her position.
Snape could use his influence over the Slytherin students. He might encourage them to play pranks on Umbridge that are so disruptive to her regime that she is forced to leave. For example, they could use magic to make her office uninhabitable or constantly disrupt her classes with minor but irritating spells.
Snape could face some backlash from the Ministry. If they find out that he was involved in getting rid of Umbridge, they might try to find ways to punish him or at least keep a closer eye on him. However, his skills at subterfuge would likely help him avoid any serious consequences.
In some fanfictions, Harry might use his powerful magic skills, like advanced spells he's learned secretly, to outwit Umbridge. For example, he could create a series of complex illusions that confuse her and lead her to leave Hogwarts on her own.
In some fanfictions, Harry discovers a long - forgotten magic charm that has the power to make a person's worst nightmares come true. He uses it on Umbridge, and she is so terrified by the nightmares that she runs away from Hogwarts. The charm could be something that is based on the person's deep - seated fears, and for Umbridge, it might be related to losing her power and being publicly shamed.
Well, he could use the power of friendship. Maybe with the help of his friends like Hermione and Ron, they come up with a plan. They might find evidence that Snape has been involved in some really bad things that go against the wizarding laws. Once they present this evidence to the proper authorities, like Dumbledore or the Ministry of Magic, Snape could be gotten rid of. Also, Harry might have some sort of prophetic dream that gives him the key to getting rid of Snape, just like he had dreams about Voldemort in the original series.
One interesting plotline could be a battle of wits within the Hogwarts faculty. Snape, with his deep knowledge and sly nature, tries to outmaneuver Umbridge's strict and often cruel regime. For example, he might secretly undermine her rules in ways that only the students and a few other faculty members notice.
However, Umbridge can also be a popular character in these fanfictions in a different way. She is the perfect villain. Her over - the - top cruelty and her self - righteous attitude make her a great antagonist. Writers can really explore her nastiness and how the other characters react to her, especially Snape who has his own way of dealing with her.
She's often portrayed as extremely cruel. She uses her position of power at Hogwarts to make Harry's life miserable. For example, she might give him excessive detentions with the blood - quill, just like in the original books. And she'll try to isolate him from his friends and undermine his credibility among the students and teachers.
In some fanfictions, Harry might get Umbridge arrested by exposing her illegal and cruel actions towards students. For example, he could gather evidence of her misuse of power in punishing students with the blood - quill and present it to the proper authorities in the wizarding world.
In many of these fanfictions, the event of Snape saving Harry from Umbridge is a turning point. Harry, who has always been at odds with Snape, is now in his debt. This changes the power dynamic between them. Snape may use this to his advantage, perhaps to get Harry to do certain things for him in the fight against Voldemort. But as they interact more, Harry discovers Snape's complex past and motives. Their relationship evolves from one of enmity to a begrudging respect, and eventually, they might even become something like reluctant comrades in the battle against the dark side.
One possible reason could be that Snape still has an underlying sense of loyalty to Dumbledore. Since Dumbledore cares about Harry, Snape might step in to save him from Umbridge's cruelty. He doesn't want to see Hogwarts turned into a place of unjust persecution under Umbridge's regime, and Harry is a symbol of the resistance against that.