His confidence would likely soar even higher. Taking over SHIELD is a huge deal, and Stark, already self - assured, would become even more so. He might become more of a strategist, having to think on a larger scale than just his personal battles. Also, he could become more authoritative, used to giving orders and expecting them to be followed without question.
When Tony Stark takes over SHIELD in fanfiction, his character could change in several ways. He might become more responsible in a different sense. While he's always been responsible for his own actions as Iron Man, now he has to be accountable for an entire organization. This could make him more cautious in some decisions. On the other hand, his sense of humor might be a bit more subdued as he has to deal with the more serious and secretive nature of SHIELD. And he could develop a stronger sense of loyalty to the agents under his command, seeing them as part of his extended team.
He might become more power - hungry. Usually, he is a hero, but with the goal of taking over the world, he could lose some of his moral compass.
Well, if Tony Stark takes over SHIELD in fanfiction, one of the first things he'd probably do is bring in his own team of trusted allies. People like Pepper Potts might get involved in the administrative side of things, bringing a more business - minded approach to SHIELD's management. He would also likely use his vast resources to fund new projects within SHIELD. For example, he could start research on new types of energy sources for their weapons and technology. And in terms of international relations, Stark's takeover could change how SHIELD interacts with other countries. His global influence as Iron Man might make some countries more or less cooperative with SHIELD depending on their previous relationships with him.
Another way could be through hacking. Tony is a genius when it comes to technology. He could hack into Shield's systems and cause widespread chaos, like shutting down their communication networks, power sources, and defense mechanisms, which would ultimately lead to the destruction of Shield as an organization.
In some fanfictions, Tony Stark might come to own Shield through his financial power and technological superiority. He could use his vast wealth to buy out the organization or find a way to take over its assets during a time of crisis when Shield is in need of a major overhaul or rescue.
If Tony Stark changes gender, her confidence might take on a different form. Instead of the brash male confidence, it could be a more understated yet still powerful self - assurance. Her sarcasm may become more refined, perhaps less cutting and more subtly humorous. Her protectiveness over her friends and the world could be expressed in a more nurturing way, while still being as fierce as before.
Gregory could be seen as a younger, more inexperienced version of Tony. So when he saves Tony, he's doing it with a kind of naive heroism. He doesn't have the same level of world - weariness as Tony. His actions are more guided by a sense of adventure and a desire to prove himself, while Tony usually acts out of a sense of responsibility.
Sometimes he becomes more confident. The power of the Extremis Armor gives him a sense of invincibility in fanfiction, so he takes more risks. For example, he might engage in battles with stronger foes without hesitation.
His character might become more confident, knowing he has the most powerful items in the universe at his disposal. He could be more decisive in his actions and less hesitant about taking risks.
His character could become more humble. Going back in time and seeing the past versions of people and events might make him realize how much he has changed over the years. He may also become more cautious. Knowing the consequences of certain actions from his original timeline, he'll be more careful with his decisions in the past. For example, he might think twice before revealing his identity as Iron Man too soon.
In this fanfiction, perhaps Stark uses his advanced technology to gain global influence. He might share his Iron Man suits' technology worldwide for peacekeeping, which could lead to him being in a position of de facto world control.