They might go on an adventure to retrieve a lost magical item that has the power to disrupt both their worlds. Maybe it's a magical stone that has the ability to open portals between the Marvel universe and the Harry Potter universe at will. They would have to face various challenges, like magical creatures from both universes that are guarding the stone.
They could embark on an adventure to rescue a group of people who were kidnapped by a dark wizard - scientist hybrid. Harry would use his spells to fight off the magical aspects of the enemy, while Tony would use his Iron Man suit to deal with the technological threats. During this adventure, they would also learn more about each other's worlds and become even closer friends.
Well, they could have all sorts of adventures. Maybe the baby cousin has some sort of special magic that Harry doesn't know about yet. For example, the baby cousin could be able to communicate with magical creatures in a unique way. And Harry, being the curious and brave wizard he is, would want to explore this new aspect of magic with his little cousin. They might go on a journey to find a rare magical creature that only the baby cousin can sense.
A possible plot could involve a new, powerful dark sorcerer who has found a way to combine magic from both universes to become invincible. Doctor Strange tries to stop him but is quickly overpowered. Meanwhile, Harry Potter senses the danger through his connection to magic. He travels to Doctor Strange's side. Harry uses his knowledge of magical creatures from the Forbidden Forest. He summons a group of Centaurs who help him in the battle. With their combined strength and Harry's strategic use of spells like the Stunning Spell, they are able to defeat the dark sorcerer and save Doctor Strange.
In such a fanfiction, Harry Potter would probably grow up with a much different set of values. Doctor Strange is often about protecting the world from threats from other dimensions. So Harry could be trained to face threats that are not just from the dark wizards in his own world. He might also have access to some really cool artifacts from the Marvel universe. And his relationships with his friends would be different too. Instead of just Hogwarts classmates, he could have allies from different realms.
They could have adventures that span both the magical and technological realms. Maybe they would team up to stop a villain who is using a combination of dark magic and advanced technology. Harry could use his invisibility cloak and magic spells to infiltrate the villain's lair, while Tony uses his Iron Man suit to provide backup and technological support.
There are countless adventures they could embark on. They could travel to outer space together, with Superman guiding Harry through the vastness of the cosmos. Harry could use his magic to protect them from any strange magical phenomena they might encounter out there. Or they could go on a quest to find a lost artifact that has the power to both enhance magic and Kryptonian powers. Along the way, they would face many challenges. They might have to deal with other superheroes or wizards who are jealous of their combined powers. They would also have to learn to trust each other completely, as their different powers and ways of thinking could sometimes lead to misunderstandings. But through these adventures, their bond as brothers would grow stronger.
He would probably be an excellent trauma doctor. Given his experiences in the wizarding wars, he has seen a great deal of physical and emotional trauma. He would be able to stay calm under pressure and use his quick - thinking skills to save lives.
They could go on an adventure to find a hidden magical artifact that was lost in the Forbidden Forest. Along the way, they'd face all kinds of magical creatures, like the centaurs and thestrals. They might have to use their combined magical skills, Harry's Gryffindor bravery and Draco's Slytherin cunning, to get past the obstacles.
They could go on an adventure to find a missing magical artifact that has fallen into the Muggle world. Gibbs' skills in tracking and Harry's knowledge of magic could be combined to track down the artifact before it causes any harm.
He could go on adventures to discover hidden vaults within Gringotts. Maybe there are vaults that have been lost for centuries, filled with ancient and powerful magical artifacts. Harry could search for these vaults, facing various traps and puzzles along the way, similar to the challenges he faced in the Philosopher's Stone.