How does Snape save Harry from Dementors in fanfiction?

One reason could be his sense of duty. Despite his dislike for Harry on the surface, he might still feel responsible for the safety of all students at Hogwarts, including Harry. So when he sees Harry in danger from Dementors, he steps in to save him.

Another possibility is that Snape uses his position as a teacher. He might threaten Lockhart with the consequences of harming a student. Given Snape's intimidating presence and his own power within the school, Lockhart would be afraid to cross him. Snape could also call for other teachers to help, making it clear that he won't let Lockhart get away with any harm to Harry.

In this type of fanfiction, Snape could simply intimidate Vernon. Snape has an air of mystery and a certain power about him. He might show up at Vernon's doorstep, give Vernon a cold stare, and with his reputation as a powerful wizard, Vernon might be too scared to oppose him. Snape could then just take Harry without much resistance from Vernon.

Well, in some fanfictions, Snape might use his powerful magic skills secretly. He could cast a spell to deflect Bellatrix's attack aimed at Hermione just in time. For example, he might use a Protego spell in a very sneaky way that Bellatrix doesn't notice until it's too late.

It could also be due to his own inner strength and growth as a wizard. Harry has faced so many challenges and traumas throughout his life. His experiences might have awakened a latent power within him that allows him to control dementors. His strong willpower and determination, which have been developed over years of fighting against the dark forces, could be the key factor in this newfound ability.

Well, in some fanfictions, Harry might use a super - powered Patronus. His Patronus could be stronger than usual, perhaps due to some newfound magic or a special connection he has developed. It could be so powerful that it simply overpowers the dementors and destroys them.

Well, perhaps Snape could use his authority as a teacher. He might see Ron being too pushy or possessive towards Harry in a romantic sense and intervene by giving Ron extra assignments or detentions to keep him away from Harry.

In this fan fiction scenario, Snape might use his knowledge of the Muggle world and Vernon's weaknesses. Snape could have found out some information about Vernon's business affairs or personal secrets. Then he blackmails Vernon into leaving Harry alone. By doing this, he effectively saves Harry from Vernon without having to use too much magic and draw unwanted attention.

Well, it could change the plot in many ways. For example, he might be able to negotiate with them. Maybe he can convince them not to attack people, which would make Hogwarts a much safer place. He could also learn more about their origin and motives directly from them, instead of just speculating as others do.

Well, he might use his magic skills. Maybe he creates some protective spells around Harry to keep the werewolf at bay. For example, a strong shielding charm that can withstand the werewolf's attacks.