Harry might initially be confused and disoriented, as the world of Hydra is so different from the wizarding world he knows. But then, he would start to analyze the situation and look for ways to escape or fight back. He might use his magic in secret, trying not to reveal too much about it at first until he figures out how Hydra would react.
He would likely be defiant. Harry has always been brave, so he'd probably resist any attempts by Hydra to control or use him.
The Avengers' reaction would be a mix of caution and curiosity. Hawkeye might keep his arrow aimed at Harry, ready for any sudden moves. Black Widow would be using her skills to read Harry's body language and try to figure out if he's lying. The Hulk might be held back initially, but if Harry made any sudden or 'threatening' moves, things could get really hairy. Overall, they'd all be on high alert until they understood that Harry was not an enemy but a young wizard with his own set of skills and a good heart.
In such a fanfiction scenario, Harry Potter might be forced to use his magic in new and unexpected ways to try to escape. Maybe Hydra would be interested in his magical abilities for their own evil purposes, like using his magic to power some sort of dark weapon.
He could be shocked. Maybe there are some fanfictions that take a very dark turn or have unexpected pairings that he never thought of. He'd probably need some time to process such strange ideas. And he might also be curious to see how far the creativity of the fans can go. He might even get some new ideas about his own life from reading some of the more imaginative fanfictions.
Hermione, on the other hand, would likely have a more critical view. She'd analyze the fanfictions for their accuracy in terms of magic lore and Hogwarts traditions. If there were any inaccuracies, she'd be quite perturbed. However, she might also appreciate the creativity that goes into some of the well - written ones that add new dimensions to their magical world.
He might be amused. Harry has a sense of humor, and the often absurd and comical situations in Blackadder fanfiction could make him laugh.
There's a chance he'd be inspired. The stories of the Naruto characters' determination and growth in the fanfiction could stir something in him. He might think about his own journey as a wizard and how he can further develop his skills and character, taking cues from the Naruto characters' tenacity.
In some Harry Potter fanfictions, 'hydra' could be a magical experiment gone wrong. A wizard or witch might have been trying to create a new form of life or a powerful spell, and instead, they ended up with something similar to a hydra. It could also be a name given to a place, like a hidden lair or a dangerous area filled with all sorts of magical perils that the characters need to navigate through.
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.
At the beginning, Harry would be frightened. He's in an unknown place with Loki, who is known for his trickery. But Harry is no pushover. He would quickly gather his courage. He would remember all the times he's faced danger at Hogwarts. He might try to communicate with Loki to understand his motives. If Loki reveals that he wants to use Harry's magic for something, Harry would try to find a way to outsmart Loki. He could pretend to cooperate while actually looking for a weakness in Loki's plan. Harry would also be thinking about his friends at Hogwarts and how he needs to get back to them, which would give him extra motivation to fight back against Loki.
The headmaster might be a bit surprised at first. He would likely respect Harry's opinion, though. He has always valued Harry's thoughts and feelings. He may start to think about the implications of fanfiction on the wizarding community and how it might affect the students and the overall perception of Hogwarts.