The plot could take a really interesting turn when it comes to Voldemort. Since Snape is raising Harry, he might train Harry in a way that Voldemort doesn't expect. Maybe Harry would be more of a spy in the dark side's camp. Snape could also use his position to mislead Voldemort about Harry's true abilities and intentions. This would create a whole new set of challenges and power dynamics in the fight against the Dark Lord. Harry's loyalties would be constantly tested, and his relationship with Snape would be even more crucial to the story.
In this fanfiction, the story could start with Harry finding Snape in a very vulnerable state after the Battle of Hogwarts. Harry feels a deep sense of guilt for how Snape was treated throughout his life. So he decides to adopt him. At first, their relationship is awkward. Snape is still his old sarcastic self, but Harry is determined. As time passes, they discover they have a lot in common. They both lost their parents at a young age, and they both had to face great challenges. This newfound understanding leads to a transformation in their relationship. Harry helps Snape to come out of his shell of bitterness, and Snape teaches Harry more about the Dark Arts in a controlled and ethical way so that Harry can better protect the wizarding world in the future.
The plot could involve a Veela who is seeking revenge on Hogwarts for an old wrong. She targets Harry Potter as he is the famous Boy Who Lived, thinking that by getting to him she can get the attention of the wizarding world. Severus Snape, being the ever - vigilant professor, senses something is wrong. He starts to investigate and discovers the Veela's plan. As he tries to protect Harry, he also uncovers some secrets about his own past that are related to the Veela. Along the way, Harry and Snape have to put aside their differences and work together to stop the Veela's vengeful plot.
The plot could involve Snape collaring Harry as a form of punishment for some misbehavior that endangers the wizarding world. But then, as they are forced to interact more because of the collar, they start to understand each other better. For example, Harry might learn about Snape's past and his true loyalties.
Well, a really interesting plot twist could be his relationship with the other Hogwarts houses. He might not have the same automatic connection with Gryffindor. Instead, he could be more inclined towards Slytherin values, which would completely change his dynamic with Ron and Hermione. Maybe he would form closer friendships with Slytherin students right from the start. Also, his views on pure - blood supremacy could be more complex as he is raised in a family that might have some traditional views on blood purity.
Well, perhaps the nuns are in cahoots with some magical creatures. They could be working with a group of centaurs who have prophesied that Harry must be raised in seclusion among the nuns to gain a certain kind of purity of spirit. Then, when Harry finally enters the wizarding world, he has an aura about him that both attracts and confounds the dark forces. He might also have a special connection to the magical animals due to his time with the nuns, like being able to communicate with them on a deeper level, which would be really useful in his battles against the dark side.
A really interesting plot twist could be that the phoenix, being a symbol of rebirth, has the ability to make Harry remember his past lives. This would give him an edge as he could draw on the knowledge and skills from his previous existences. He might remember spells and strategies that were long forgotten, which would completely change the course of his fight against the dark forces.
One possible plot twist could be that Harry has unique magical abilities related to the ocean. For example, he might be able to communicate with sea creatures, which could help him in his adventures. Maybe he discovers a hidden underwater wizarding community that has been isolated from the rest of the wizarding world for centuries. Another twist could be that his enemies, like Voldemort, have a hard time reaching him in the ocean, but they find a way to use the ocean's power against him in some unexpected manner.
Perhaps in the fanfiction, Draco Malfoy turns out to be a double agent. He pretends to be on the side of the Death Eaters like his family, but in reality, he is secretly helping Harry Potter and the Order of the Phoenix. Snape discovers this and has to decide whether to expose Draco or use his secret to their advantage. This would create a lot of tension and unexpected alliances.
One interesting plot twist could be that Snape's blood adoption gives Harry some of Snape's memories. This would allow Harry to see Snape's true motives throughout the years, not just the ones Dumbledore had revealed. Another could be that the adoption gives Harry a new magical ability related to Snape's potions expertise, like the ability to brew extremely powerful potions without much effort.
One possible plot could be that after the war, both Harry and Snape realize they have a deeper understanding of each other. They start to communicate more, initially about the events that transpired. As they talk, they find common ground in their experiences of loss and loneliness. Slowly, feelings develop, and they decide to give a relationship a try. Eventually, they get married in a small, private ceremony attended only by their closest friends who have come to accept their relationship.