Well, he could use his magic skills. Maybe he casts a powerful spell on Ron to stop him and then takes Hermione to a safe place, like Hogwarts where there are protective enchantments.
Harry might call for help from his other friends like Luna or Neville. Together, they could overpower Ron. He could also use the Marauder's Map to keep track of Ron's movements and plan the rescue accordingly. Harry has always been brave and would do whatever it takes to save Hermione from such a horrible situation.
Perhaps Harry uses his invisibility cloak to approach Ron unnoticed. Then he could disarm Ron and quickly get Hermione out of there. Harry is very resourceful and his knowledge of defensive magic would surely come in handy in such a situation.
In the fanfic, perhaps there was some deep - seated jealousy in Ron. He might have felt overshadowed by Hermione's intelligence and Harry's fame for a long time, and it all just boiled over in this really wrong way.
Maybe Harry uses his magic skills to immobilize Ron. He could cast a spell like 'Petrificus Totalus' on Ron right when he's about to attack Hermione, thus stopping the beating.
Another way Severus could save Hermione is by using his knowledge of the Dark Arts in a positive way. If she was hurt by a Dark spell from Ron (in the context of the fanfic), Severus might be able to counteract the spell's effects. He has extensive experience with Dark Arts spells, so he could figure out what spell Ron used and then use a counter - spell to reverse the damage.
Well, in many fanfics, Harry might use his quick thinking and swimming skills. He could have found Hermione using his magical connection to her or by following the signs in the underwater maze. Maybe he used a spell to break whatever was binding Hermione and then swam her back to the surface.
Well, in many such fanfictions, Harry might use his magic skills. He could cast a powerful stupefy spell on the troll to stop it in its tracks and then quickly lead Hermione to safety. Maybe he also uses his quick thinking and knowledge of the Hogwarts corridors to find a hiding place where the troll can't reach them.
Well, in some versions, Ron might use his quick wit and knowledge of Hogwarts' secret passages to outmaneuver Draco. He could lead Hermione to safety through a passage that Draco doesn't know about.
Well, it could be that Lucius uses his powerful influence in the wizarding world. Maybe he intimidates Ron with threats related to his family's status or he uses some dark magic to create a distraction and whisk Hermione away.
Well, it could be that Snape has been secretly observing Ron's erratic behavior towards Hermione. When the situation gets out of hand, he intervenes. He might use his position as a teacher to discipline Ron and in the process, saves Hermione. Snape is a complex character with a lot of power and knowledge, so he could use various means like his occlumency skills to sense the danger Hermione is in and act accordingly.
In fanfiction, their friendship often develops through shared challenges. For example, when they face a new dark magic threat in the wizarding world, they rely on each other more. Harry's leadership, Ron's humor in tough situations, and Hermione's knowledge combine to make them closer. They also develop their friendship by having deep conversations about their fears and hopes for the future. Maybe Harry shares his concerns about being the Chosen One, and Ron and Hermione support him wholeheartedly.
In this fanfic, the relationship between Hermione and Ron might be explored through the eyes of other characters. For instance, Harry might notice the small glances and touches between them that he hadn't paid much attention to before. It could also show how their relationship affects the group dynamic. With Hermione choosing Ron, it changes the way the trio interacts. And it could explore their future together, imagining how they would build a life as a couple in the wizarding world, dealing with things like family, career, and their place in the wizarding society.