Perhaps Harry Potter is wrongly accused of a serious crime in the wizarding world and is on the run. He somehow ends up in a place where the Queen has jurisdiction. She, seeing his innocence or realizing the importance of his role in the fight against evil, decides to offer him protection and thus saves him. This could lead to an interesting alliance between the wizarding world and the Queen's realm, with Harry as the bridge.
Well, it might be that Harry Potter is accidentally transported to a non - magical realm where he is in trouble because he doesn't understand the Muggle world completely. The Queen, who has some knowledge of magic or is in contact with a secret magical society, discovers Harry and saves him from the perils of this strange new world for him.
It might be an ancient magical being that has the form of a queen. She could have ties to the very origins of magic in the Harry Potter universe and decides to save Harry because she foresees his importance in the future of magic. For example, she could be a guardian of some sort of magic that is crucial for Harry to defeat Voldemort in the long run.
One possibility could be that Voldemort has a sudden change of heart. Maybe he realizes that Harry is the only one who can truly understand his loneliness and power. So instead of killing Harry, he decides to save him from a dangerous situation, like a powerful dark magic that even Voldemort fears could destroy the wizarding world if not controlled, and in the process, they form an unlikely alliance.
In the 'Harry Potter Saved by Demons' fanfiction, perhaps the demons are not as evil as they seem in the traditional sense. They might be outcasts from their own demon realm. When they come across Harry, they recognize his power and the danger he's in. They decide to save him because they believe that by doing so, they can change the fate of both the wizarding world and their own world. So they use their unique demon abilities to keep Harry safe from harm.
Well, perhaps the Winchesters, who are known for hunting supernatural beings in their own universe, find a way into the Harry Potter world. Maybe they sense some dark magic that the wizards in Harry Potter's world can't handle on their own. They then use their skills and knowledge of the supernatural to save Harry from a powerful dark wizard or a dangerous magical creature.
Well, it could be that Hera, perhaps using her divine powers, steps in when Harry is in a really tough situation in the wizarding world. Maybe she saves him from a powerful dark spell or a dangerous creature. For example, when he's facing Voldemort, Hera could use her magic to shield Harry and give him the strength to fight back.
In 'harry potter the queen guardian fanfiction', it may show the Queen as a guardian of magical creatures. She could be in charge of protecting thestrals, for instance. Thestrals are quite unique and important in the Harry Potter world. The Queen might be using her influence and some special magical abilities to keep their habitats safe. This could also involve her having to deal with poachers or those who want to use thestrals for dark magic. Harry Potter and his friends could get involved in this situation too, either by accident or because they are asked to help by the Queen.
Well, it could be that in the fanfic, Harry Potter uses his magic skills to protect the Queen from dark wizards who are plotting against her. Maybe he creates a powerful protective shield around the palace.
One possibility could be that in an alternate magical universe, Harry Potter, after all his adventures at Hogwarts and defeating Voldemort, travels to a different realm where he meets a queen. Maybe the queen is facing some magical threats in her kingdom and Harry, with his powerful magic, offers to help. As they work together, they fall in love and decide to get married. Their union could then bring about a new era of peace and cooperation between the wizarding world and the queen's non - magical kingdom.
Perhaps in this fanfiction, Harry Potter is recruited by the queen to solve some magical mysteries within the palace. He could use his knowledge of the wizarding world to uncover secrets that are plaguing the monarchy. For example, there might be a cursed object in the palace that is causing strange happenings, and Harry is the only one who can find and break the curse.
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.