Well, Naruto would probably be exposed to a whole new world of high - tech gadgets. Tony could use his tech to enhance Naruto's ninja abilities. For example, he might create special kunai with tracking devices or energy - enhancing properties. Naruto would also be introduced to a different kind of family dynamic. He'd be living in Stark Tower, surrounded by Avengers, which would be a wild change from the Hidden Leaf Village.
Well, one possibility is that Harry, who might be in a difficult situation in his own world, is suddenly whisked away to the Marvel universe. Tony Stark, seeing his potential or just feeling a connection, decides to adopt him. Harry could then be introduced to high - tech gadgets and superhero training, and he might use his own magical knowledge in unexpected ways in this new world.
In some fanfictions, their relationship could be a bit rocky at first. Maybe the adopted daughter has a different view on how to use technology for good. But through various events and heart - to - heart conversations, they grow closer and learn from each other, with Tony learning to be more open - minded and the daughter learning the value of his experience.
Maybe the fanfiction could be about Tony adopting a child with special powers. He has to protect the child from those who would misuse the powers while also helping the child understand and control them. This could involve lots of action scenes and emotional bonding between Tony and the adopted child.
Well, a plot twist could be that Harry's past with the Dursleys is revealed to Tony in a very dramatic way. Maybe some magical artifact from Harry's world that he brought with him accidentally shows Tony all the abuse and neglect Harry endured. This could lead to Tony becoming extremely protective of Harry and going after the Dursleys in his own way, using his resources and influence. Another twist might be that Harry has a hidden power that is only awakened when he is in the presence of Stark's advanced technology. This power could be something that even the wizarding world doesn't know about, and it could put Harry in a position where he has to choose between his two worlds. And then, there could be a plot twist where Tony's enemies target Harry to get to Tony, thinking that Harry is Tony's weak point, but in reality, Harry ends up being the one who saves Tony.
One interesting plotline could be the adopted daughter developing her own unique suit under Tony Stark's guidance. It shows her growth and the bond between them as she learns from the genius.
One common theme is redemption. Often, the adopted character might have a troubled past, and through Tony's influence, they find a new path. For example, in some fictions, the character could have been involved in minor crimes before.