Perhaps a plot twist could be that Regina's world, which might be different from the typical 'Harry Potter' world, has its own set of rules and magic. When Harry is adopted into this new environment, his magic starts to change or develop in unexpected ways. He could end up with new powers or abilities that no one expected, and this could create a whole new set of challenges and adventures for him.
Another plot twist could be related to Harry's identity. Since he's adopted by Regina, his connection to the Dursleys and his original family history could be distorted. This might lead to a situation where he discovers his true heritage in a completely different way than in the original 'Harry Potter' series, perhaps with Regina being involved in the discovery in a complex way.
One possible plot twist could be that the lich, despite being a dark and undead being, has a soft spot for Harry and teaches him unique forms of magic that are not part of the regular Hogwarts curriculum. This could put Harry in a strange position among his peers as he has knowledge that is both powerful and a bit unorthodox.
One plot twist could be that Regulus is not actually dead but was in hiding all this time. And his reason for adopting Harry could be related to some dark secret he's trying to protect. Maybe it has something to do with Voldemort and a way to defeat him that only Harry can be a part of.
His relationship with his enemies like Voldemort would also be affected. If Regina has some sort of power or influence over Harry, Voldemort might see him as an even greater threat or an easier target. Harry might also have different ways of defending himself, influenced by Regina's methods or the new environment he's in. For example, Regina might have her own way of dealing with dark magic that she teaches Harry, which changes how he approaches Voldemort and his Death Eaters.
In the 'Harry Potter and the Twists of Fate Fanfic', a possible plot twist could be that the way magic works is suddenly changed. Maybe spells that were thought to be dark are actually the key to solving a great mystery. This would force the characters to re - evaluate their understanding of magic and their place in the wizarding world. It would also create new challenges and opportunities for the characters, leading to a whole new set of adventures and conflicts.
One possible plot could be that Marge, despite her initial rough exterior, discovers a soft spot for Harry. She might start to teach him some of her own values, which could be a mix of traditional and rather strict ones. Harry would have to adjust to living in a new environment with Marge's dogs and her no - nonsense attitude.
In this fanfic, perhaps Harry Potter is orphaned in a different way than in the original story. Goku stumbles upon him and, not really understanding the concept of magic at first but sensing Harry's good heart, takes him in. Harry would be introduced to Goku's friends like Bulma and Krillin. Bulma might be fascinated by Harry's magic and try to find a way to combine it with her technology. As for Harry, he'd have to adapt to a very different world. Instead of Hogwarts, he might train at Kami's Lookout. And his relationship with Goku would be one of a son - father figure, with Goku teaching him important values like never giving up and always protecting the weak, which would also tie in with Harry's own nature of fighting against evil in the wizarding world.
In a 'Harry Potter adopted by Newt' fanfic, perhaps Newt gets a mysterious message about a powerful but troubled young wizard. When he finds Harry, he realizes that the boy has a connection to the magical creatures world that he doesn't yet understand. Newt takes Harry under his wing. Harry gets to live in Newt's home, which is filled with all sorts of amazing and dangerous creatures. He learns about their habitats, behaviors, and how to communicate with some of them. This knowledge and his bond with Newt could change the way he approaches challenges at Hogwarts and in the wizarding world as a whole.
One possibility is that Umbridge, despite her cruel nature, sees some potential in Harry for her own gain. Maybe she tries to mold him into a perfect little wizard according to her strict and often wrong ideas. She could isolate Harry from his friends and force him to follow her rules blindly, which would create a lot of internal conflict for Harry as he tries to resist her brainwashing while living under her roof.
It could be that the wolves are actually magical wolves with special powers. They sense Harry's unique magic and choose to protect him from the threats he faces in the wizarding world. Harry, while being adopted by them, might discover new forms of magic that are related to nature and the wild, which are different from what he learns at Hogwarts.
It's possible that a big plot twist in the fanfic is related to Harry's parents. Maybe they knew about his werewolf nature before he was born and had some sort of plan in place. Or perhaps Harry's werewolf condition was actually caused by something related to his parents' past or a secret they were hiding. This could completely change the way we view the events leading up to Harry's discovery of his werewolf side in the fanfic.