The BAMF could be an anti - hero type of character who believes that Tony Stark's actions are causing more harm than good in the world. So, they decide to take matters into their own hands and hurt Tony. The fanfic could explore the moral and ethical implications of this. For example, the BAMF might expose Tony's secrets to the public, which would damage his reputation, and then physically attack him to stop him from continuing his work.
One possible plot could be that the BAMF is a powerful new villain who targets Tony Stark out of jealousy for his technology and fame. The BAMF might start by attacking Stark Industries, causing chaos and destruction. Then, they could directly confront Tony in his Iron Man suit, using some new and unexpected powers to hurt him both physically and mentally, perhaps by hacking into his suit's systems.
Maybe the BAMF is a character who has a personal vendetta against Tony Stark. In the fanfic, the BAMF could be someone from Tony's past that he wronged unknowingly. So, this character uses their skills and resources to gradually wear Tony down. They could start by ruining his relationships with his friends and allies, and then move on to physical attacks, causing serious harm to Tony.
The plot could involve Tony and Nebula going on an adventure to find a powerful energy source that was lost during the events of the Infinity War. Along the way, they encounter various alien species that try to stop them. Tony uses his quick thinking and Nebula her combat skills to fight through. In the end, they find the energy source and use it to power a new device that can protect Earth from future threats.
Tony Stark could use his intelligence to analyze the BAMF's weaknesses. He might quickly run scans during their encounters to figure out what can harm the BAMF. Then, he could upgrade his Iron Man suit with new weapons and defenses specifically designed to counter the BAMF's attacks.
In a fanfiction, perhaps Nebula saves Tony Stark's life during a space battle. Tony, being the brilliant mind he is, then decides to create a new weapon or technology with Nebula's help. They bond over their shared experiences of survival and their determination to protect the universe. Their relationship could grow from mutual respect to a deep friendship as they face various challenges.
Perhaps in the fanfic, Tony Stark is turned into a cat by one of his experiments gone wrong. He then has to navigate his life as a cat while still trying to be Iron Man. He might have to communicate with his friends in different ways and face challenges that come with his new feline form. It could be a really comical and interesting story.
Well, 'Stark's Ascendance' is also a wonderful bamf Tony Stark fanfic. It delves deep into Tony's psyche while also showing him as a total badass. He faces numerous threats, both from within his own company and from external villains. But with his quick thinking and unwavering determination, he always comes out on top. The story also has great character development for Tony, as well as some interesting relationships with other characters from the Marvel universe.
One possible reason could be jealousy. Maybe Tony's intelligence and wealth made some Avengers feel inferior, and over time, that festered into betrayal. For example, if Tony developed a new technology that could potentially overshadow their own abilities, they might feel threatened.
One plot idea could be that they team up to solve a global crisis. Maybe a new super - weapon has been developed by a common enemy, and their combined skills in technology (Tony) and detective work (Batman) are needed to stop it. They start off a bit wary of each other, but as they work together, they realize they have more in common than they thought.
The plot could involve them working together on a new super - technology. For example, they might try to create a device that can control the Hulk's power more precisely, leading to all kinds of adventures and challenges along the way.
Perhaps the plot twist is that Gregory Stark is from an alternate universe where the rules of physics and technology are different. His methods of saving Tony Stark seem strange and dangerous at first, but in the end, they lead to a revolutionary breakthrough in both Stark's personal technology and the way the world views superheroes.
You can try Archive of Our Own (AO3). It has a vast collection of fanfics, and there are bound to be many bamf Tony Stark ones. Just use the search function and type in relevant keywords like 'bamf Tony Stark' and you'll get a list of results.