Tony may develop a darker side. The allure of the Infinity Stones' power could corrupt him. He might start to make decisions that are not in the best interest of the world but rather for his own gain or to satisfy his newfound thirst for power. This would create a lot of conflict, both within himself and with his friends, and add a whole new dimension to the fanfiction.
Well, perhaps the plot could involve Tony Stark's quest to collect all the Infinity Stones for some noble purpose. Maybe he wants to use their power to prevent a greater threat to the universe than Thanos ever was.
In many Infinity Gauntlet fanfictions, Tony Stark's character development is centered around his relationship with power. At first, he may be tempted by the unlimited power of the gauntlet. But as the story progresses, he could come to understand that true power lies not just in the gauntlet but in the relationships he has built with his friends and allies. He may learn that the power of teamwork and friendship is more important than any magical object, and this realization could completely transform his character for the better.
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.
Tony could become more cautious. Since he has an unborn to think about, he may not take as many risks in battles. He starts to think more about the consequences of his actions not just for himself but for the life he's carrying. In addition, he might also become more of a team player, relying on his friends more than before for support during this strange time.
Tony's character often develops from a more detached mentor to an extremely possessive figure. At first, he might be just guiding Peter in the superhero world, but as the story progresses, his feelings intensify. His possessiveness could be triggered by a threat to Peter's life, which makes him realize how much Peter means to him.
One interesting plot twist could be that Tony discovers an unknown power of the Infinity Stones that even Thanos was unaware of. Maybe it's a power that can reverse time not just for a single person but for an entire planet. This would completely change the power dynamics in the story.
The story could develop with Tony trying to reason with Steve. Tony might use his intelligence to talk Steve out of whatever his plan is. He could point out the flaws in Steve's reasoning or show him evidence that he's been misled.
Pepper Potts would probably be involved. She might be worried about Tony's new obsession with the Infinity Stones and try to keep him grounded. Happy Hogan could also be there, providing some comic relief and practical support.
Tony could be the team captain. As the captain, he has a special bond with the team members and might want to do something special to boost their morale. He would know what kind of surprises would really make an impact on them.
In this fanfiction, Tony Stark's character would develop in several ways. Initially, he might be a bit clumsy at parenting, but as time goes on, he'd become more attuned to Peter's needs. His focus would shift from just his own inventions and heroics to also considering Peter's future. He'd become more selfless, as he'd be willing to sacrifice his time and resources for Peter's well - being. He might also become more cautious in his actions, knowing that he has a young life depending on him.