In a 'Harry Potter Saves Bellatrix' fanfiction, perhaps Bellatrix is in a situation where she's about to be killed by other Death Eaters who think she's a liability. Harry, having a sense of justice and seeing the potential for redemption in her, steps in to save her. He could then try to show her the error of her ways, using his own experiences of losing loved ones to Voldemort's ideology. Bellatrix might initially resist, but gradually come to understand Harry's point of view.
Well, it could start with Bellatrix being trapped in a dangerous magical trap set by some ancient dark magic entity. Harry stumbles upon her while on a mission to uncover more about the origins of dark magic. He decides to save her because he believes that every life is worth saving, even someone as cruel as Bellatrix. After saving her, Harry tries to rehabilitate her, introducing her to the world outside of Voldemort's control. He shows her the good in the wizarding world, like the kindness of the Weasleys, the wisdom of Dumbledore, and the beauty of Hogwarts. This might make Bellatrix question her past actions and start a new path.
It could be an ancient dark magic artifact. The artifact has a hold on Bellatrix, and in a way, it's the 'enemy' that Harry has to defeat to save her. The artifact might be trying to use Bellatrix to carry out some dark plan, like opening a portal to a world full of dark creatures. Harry has to figure out how to break the connection between Bellatrix and the artifact while also fending off the artifact's attacks.
In this fanfiction, perhaps the centaur is in a situation where it's about to be sacrificed in some dark ritual. Harry discovers this and races against time to stop it. He calls upon his friends Hermione and Ron for help. Hermione uses her vast knowledge of magic to figure out how to break the dark magic circle, while Ron provides some much - needed comic relief during the tense situation. Harry, of course, is the one who ultimately uses his powerful Patronus charm to dispel the dark forces and save the centaur.
Well, perhaps Zoe is in danger from dark wizards. Harry, with his skills and bravery, could use spells like Expelliarmus to disarm the villains threatening Zoe. He might also use his invisibility cloak to sneak up on them.
The fanfiction could show that Harry discovers a secret passage that leads to where Cedric is held captive. He has to face various magical traps and challenges on the way. Once he reaches Cedric, he uses his Gryffindor courage and his knowledge of magic, like the Shield Charm to protect Cedric from incoming spells, and then they escape together, with Harry being the hero who saves Cedric.
One possible plot could be that Harry, through some magical accident or powerful spell, is transported to the world of Cintra. There, he discovers the danger it's in. Using his magical skills like the Patronus charm to ward off dark creatures threatening Cintra, and his knowledge of spells to help in battles. He might also form alliances with the local warriors, teaching them some basic magic for self - defense.
Well, perhaps the vampire is being hunted by some dark wizards. Harry Potter, being the hero he is, uses his magic skills like the Patronus charm to fend off the attackers and save the vampire. Maybe the vampire has some crucial information about Voldemort that Harry needs.
Well, perhaps Harry stumbles upon a unicorn in the Forbidden Forest that is trapped by some dark magic spell. He uses his magic skills, like a Patronus charm to fend off the dark forces around the unicorn and then heals it with some herbology knowledge.
Maybe Harry uses his magic skills like the Patronus charm to protect the Jedi from the Sith. His ability to apparate could also help Jedi in quick escapes.
One possible plot could be that the Queen is in danger from dark wizards who want to take over the Muggle government. Harry, using his skills from Hogwarts, discovers the plot and uses magic to protect the Queen. He might use spells like Protego Maxima around Buckingham Palace.
Well, perhaps Harry could use his magic to defend Wakanda from some dark force. Maybe Voldemort has an alliance with an enemy of Wakanda and Harry has to stop them. He could use spells like Protego Maxima to shield Wakanda's borders and use the Patronus charm to fend off the Dementors that the villains might send.