A possible fanfiction could be set in an alternate universe where Tony Stark is a fallen hero and Lucifer, seeing his potential, decides to recruit him for his own purposes. Stark initially resists but as he sees the chaos around him that he can't fix with his normal means, he starts to consider Lucifer's offer. But then he remembers his past and the people he has saved, and decides to fight against Lucifer instead, using his genius to find a way to defeat the devil.
One idea could be that Tony Stark somehow discovers the wizarding world while working on a new technology. Maybe his sensors pick up some strange magical energy. He then meets Harry Potter and they team up to face a new threat that combines magic and technology, like a dark wizard using Stark Industries' tech for evil purposes.
One idea could be a crossover where Naruto is transported to the world of Westeros. He meets Arya Stark and they team up. Naruto could teach Arya some of his ninja skills, like how to move stealthily like a shinobi. This would enhance Arya's ability to seek revenge on her enemies in a more efficient way.
They could interact through a power struggle. Tony Stark has his high - tech arsenal and his sharp intellect, while Lucifer has his otherworldly powers. For example, Stark might create a device to contain Lucifer's powers, but Lucifer would use his wiles to turn Stark's allies against him.
Another concept is a fanfic where Sansa Stark is transported to the Naruto universe. She could find herself in Konoha and start learning about chakra and ninja skills. Naruto, being the friendly and curious type, would be one of the first to befriend her. He might teach her some basic ninja moves, and in return, Sansa could share her knowledge of court politics, which could be useful in the complex shinobi society.
It could be really exciting. Picture Tony Stark using his high - tech gadgets in the wizarding world of Harry Potter. Maybe he'd create some sort of device to detect magic in a scientific way. Or he could team up with Harry Potter to fight against Voldemort using his Iron Man suit and Potter's magic spells together.
One idea could be that Naruto, with his godlike powers, somehow ends up in the world of Highschool DxD. He meets Lucifer and they initially have a clash due to misunderstandings. Naruto's power might surprise Lucifer and his followers. As the story progresses, they could find common ground and team up against a greater threat that endangers both Naruto's world and the Highschool DxD universe.
A great fanfiction idea could be that their baby has some unique superpower that they have to keep hidden from the public. This would add an element of mystery and danger to the story. They'd have to be extra careful about who they trust, and it could lead to some tense moments when the baby's power accidentally reveals itself.
Another aspect could be the family dynamic. Since Tony is known for his brash and confident personality, he might be overprotective of Harry as his nephew. Harry, on the other hand, is used to dealing with the wizarding world's challenges on his own. This could lead to some interesting conflicts and growth for both characters. For instance, Tony might try to keep Harry away from Hogwarts, thinking it's too dangerous, but Harry would be determined to go and learn magic.
A third idea is a scenario where both universes are somehow merged. In this new world, Hogwarts students have the option to study both magic and technology. Harry and Tony meet as teachers or mentors in this new educational system. They have to work together to prevent the misuse of both magic and technology by some of the more power - hungry students or villains.
Another fanfiction could focus on their friendship. For example, they could have a weekend getaway where they just relax and talk about non - work - related things. They might share stories from their past, like Tony's wild college days and Bruce's early research experiences. It would be a chance to explore their characters on a more personal level.