A new student in the school could be the one to save Sakura. This new student might have had similar experiences in their previous school and decides to take a stand against the bullies when they see Sakura being harassed.
Perhaps an older teacher or coach who has always had an eye on Kuroko's potential could step in as a savior. They could see the signs of bullying and use their authority to punish the bullies and provide support and guidance to Kuroko, helping him to grow stronger both on and off the court.
It could be some of the more aggressive monster characters. For example, the dog monsters might be territorial and see Frisk as an intruder, so they bully Frisk.
Lisbon could be a top contender as a savior. She knows Jane very well and is highly motivated to rescue him. Her detective skills and knowledge of Jane's habits would be very useful in tracking him down. Another could be Cho. He's very resourceful and has a calm head under pressure, which would be great for handling the situation.
Sakura could have interactions with the Weasley family. Ginny Weasley might become her friend and they could have girl - talk about magic and boys. Fred and George could also be part of her story. They might play some pranks on her at first but then become good friends. And don't forget Neville Longbottom. Sakura could help Neville gain more confidence in his magic abilities as they study together in the Hogwarts library.
Perhaps Sakura decides to learn self - defense techniques to protect herself from the bullies. This could lead to her gaining confidence and eventually standing up to them on her own.
Perhaps an enemy from a rival group. They might see Sakura as a threat to their plans, so they poison her to get her out of the way. Another possibility is a character who has been secretly harboring a grudge against her for a long time, and finally decides to take action by poisoning her.
Sakura is, of course, the central character. The bullies are usually other students or characters who might be jealous of Sakura for some reason, like her popularity or special abilities. There are often also some friends or allies of Sakura, such as Naruto or Sasuke in a Naruto - themed fanfiction who might stand up for her.
In this fanfic, it could even be her best friend's partner who has been secretly interested in Sakura and cheats on her best friend with Sakura. This would add an extra layer of drama and betrayal as it not only affects Sakura's relationship but also her friendship.
Hermione could be a potential savior. She's smart and resourceful. She might figure out where Lockhart has taken Harry by using her vast knowledge of magic and Hogwarts' secrets.
There could be some new and unknown characters in her team. Maybe some young and eager rookies who look up to Sakura for her experience.