He would likely become more isolated and withdrawn. Tony has always been a bit of a lone wolf, and this would push him further into his shell. He might start to focus solely on his own projects, cutting off any remaining ties with the Avengers. He'd also be angry and might seek revenge, using his intelligence and resources to get back at those who wronged him.
Tony would probably be extremely hurt. He trusted his team, and betrayal would cut deep. He might initially be in denial, not wanting to believe that his friends could turn on him.
The Avengers would be in a state of panic and fury. Captain America would likely lead the charge to find Tony. He'd use his military strategy skills to plan a rescue mission. Thor might use his godly powers to track down any signs of Tony's whereabouts. Black Widow and Hawkeye would be on the lookout for any Hydra agents or informants. Hulk could be a wildcard. He might be uncontrollably angry and ready to smash anything in his path to get to Tony.
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.
The concept of Tony Stark as a cat in a fanfic can also bring out different aspects of his personality. Cats are often seen as independent, which is a trait that Tony already has. But as a cat, it could be exaggerated. He might be more aloof and choose when and who he wants to interact with among the Avengers. This could create some tension or just more light - hearted moments as the other Avengers try to figure out what the cat - Tony Stark is thinking or wanting.
At first, Tony would be in shock. But then, he'd start trying to jog her memory in his own way. He'd show her all their personal mementos, like the first rose he gave her or the necklace he designed for her. He'd also tell her stories about their adventures together, hoping that something would click. And he'd be very protective of her, not wanting any harm to come to her in her vulnerable state.
Steve Rogers would probably be deeply disappointed. He values loyalty highly, and Tony's betrayal would shatter the trust they had. He would try to find out the reasons behind it and might even try to bring Tony back to the right path if he thought there was a chance.
Some of them might be disappointed. Captain America, for instance, might feel that they've lost a great asset. But at the same time, he might also see it as an opportunity for the Avengers to be more independent from Stark's sometimes self - centered ways. Thor would probably be a bit confused as he was used to Stark's quick - witted remarks during battles.
They might be in shock. Tony has a complex past, and seeing it all unfold could leave them speechless.
In this fanfic, Tony Stark would interact with Harry Potter in a very interesting way. At first, he might be a bit overbearing, trying to control every aspect of Harry's life because he wants to keep him safe. But as he gets to know Harry better, he'd start to respect Harry's independence. Tony would also be fascinated by Harry's magical abilities. He might try to find a scientific explanation for it, and in the process, he and Harry would have many deep conversations. Harry would learn from Tony's confidence and self - assurance, while Tony would learn about the power of magic and the importance of things that can't be measured by science.
He would probably be overprotective at first. Tony has been through a lot, and the idea of his daughter having mutant powers, which could make her a target, would be scary for him. He might try to keep her locked away in the Stark Tower, but that would likely lead to her rebelling.
He'd probably be shocked at first. Tony is always so caught up in his own world that a secret daughter would be a huge surprise. But then he'd likely be protective. He might try to keep her away from his dangerous life at first, but as he gets to know her, he'd start to include her in things.