Well, Harry could use the island as a place to hide powerful magical artifacts that he doesn't want to fall into the wrong hands. He could also invite his friends from Hogwarts to come and visit, and they could have all sorts of adventures exploring the uncharted parts of the island. And he might use magic to create unique and amazing structures on the island, like a floating castle or a forest that has trees that can talk and give advice.
In this fanfic, perhaps Harry could turn the island into a magical sanctuary for endangered magical creatures. He might build a school there for young witches and wizards who are overlooked by the mainstream magical education system.
Well, if Harry Potter owns the Ministry in fanfic, he might start by reforming the laws. For example, he could change the laws regarding house - elves, giving them more rights. He'd also probably make big changes to the education system at Hogwarts. Maybe he'd introduce new subjects that are more relevant to the modern wizarding world.
Maybe he'd discover some magical creatures native to the island. He could form an alliance with them, like how he befriended various magical beings at Hogwarts. He could also use the natural resources of the island along with his magic to build a shelter and find food. Since he's a wizard, he might even be able to magically purify water sources on the island.
Perhaps he uses the island as a secret training ground. He could practice advanced spells away from the prying eyes of Hogwarts faculty and students. Harry might also build his own magical fortress on the island for protection and privacy.
He might have discovered the island during one of his adventures and claimed it as his own. Since there was no one else on the island at the time, and he was the first to set foot on it and recognize its potential, he decided to make it his property.
The fanfiction could be about Harry turning the island into a sanctuary for magical creatures. He might find some endangered or mistreated magical creatures and bring them to the island to live in peace. He'd then have to deal with the challenges of taking care of them all, like finding food sources and creating habitats suitable for each species.
There could be some of the house - elves that Harry has freed. They might choose to live on the island, using their magic to help with various tasks such as farming magical plants or taking care of the island's infrastructure. Also, some of the students from Hogwarts who were inspired by Harry could be there. They might be learning new forms of magic that are specific to the island or studying the unique magical ecosystem there.
Perhaps it's an island with a hidden wizarding school, similar to Hogwarts but with its own distinct features. There might be ancient spells protecting the island, and the architecture could be a blend of different magical styles. Harry could have discovered this island during one of his adventures and decided to make it his own. He might use it as a sanctuary for those in need or as a place to study and preserve rare magic.
One possibility is that the Mandalorian's ship, the Razor Crest, could end up near Hogwarts. The students would be amazed by this strange flying machine. The Mandalorian might be searching for a lost Jedi or Sith relic that has some connection to the wizarding world. He could then get involved in the ongoing struggle against Voldemort or other dark forces in the Potter universe.
Well, in the fanfic, Naruto might use the knowledge from the Forbidden Scroll to develop some unique and powerful jutsu. He could gain an edge in battles against his enemies like Orochimaru or Pain.
Well, perhaps Harry could be reporting some dark wizard activity. He might call the Department of Magical Law Enforcement (DMLE) to inform them about a Death Eater sighting. This could lead to a big investigation within the wizarding world.