It could be that a powerful sorcerer in the Avengers' world goes rogue and starts using dark magic. The Avengers don't know how to handle magic, so Harry is called in. He has to face this rogue sorcerer, using his own brand of light magic. Along the way, he might have some clashes with the Avengers' way of doing things, but in the end, they all work together and Harry manages to save the day by defeating the rogue sorcerer and restoring peace in the Avengers' world.
If Harry Potter saves the Avengers in fanfiction, he would bring a whole new dimension to their battles. His knowledge of the magical world could be used to outwit enemies. He could create magical barriers to protect the Avengers' base or use the invisibility cloak to sneak up on foes. And his Patronus could be a great weapon against dark forces that the Avengers face. It would be a unique crossover where magic and superhero powers combine.
Sure. In this fanfiction, Harry might bring in his knowledge of the wizarding world. He could use potions to heal injured Avengers or use charms to break through enemy defenses. The story might explore how the Avengers react to this strange new magic - user in their midst. They might be initially skeptical but then come to rely on Harry as he proves his worth time and again in saving them from various perils.
Well, perhaps Harry uses his magic skills like the Patronus charm to fend off some dark force that is attacking the Avengers. He could also use his knowledge of potions to heal any injured Avengers.
Well, in this fanfiction, it could be that Spiderman uses his agility and web - slinging skills to outmaneuver the enemy. Maybe he creates a huge web shield to protect the Avengers from a powerful blast. His spider - sense could also alert him to hidden dangers that the Avengers might not notice, allowing him to save them at the crucial moment.
The plot could involve Castiel being summoned by a magical accident in the Avengers' universe. He then realizes that there is a great evil approaching, something that not even the combined might of the Avengers can handle. So, he decides to use his knowledge of the supernatural and his powers to help them. He might have to teach the Avengers about the existence of angels and other celestial beings to make them understand the true nature of the threat. Along the way, there could be some really interesting interactions between Castiel and the different Avengers members. For example, his stoic and otherworldly nature could contrast with Tony Stark's sarcastic and scientific mind, leading to some great dialogue.
I haven't actually read this fanfiction, so I can't summarize it specifically. But generally, it might involve Stiles, a character probably from another universe like Teen Wolf, using his unique skills or knowledge to rescue the Avengers who are in some sort of danger. It could be a really exciting and creative crossover story.
It could be a powerful dark wizard who has somehow made his way into the Avengers' universe. Maybe a wizard who was banished from the wizarding world in Harry's universe and has now joined forces with some of the Avengers' villains.
A possible plot twist could be that Spiderman is actually from an alternate dimension where he has different powers. And these powers are the key to saving the Avengers. For example, he might be able to time - travel in this dimension and go back to prevent the event that put the Avengers in danger in the first place.