In a fanfic where Harry fights the Chitauri, he might use his magic in unexpected ways. For example, he could use spells like 'Expelliarmus' to disarm the Chitauri weapons. His ability to apparate could also give him an advantage in dodging their attacks. Maybe he would team up with some of the Avengers as well, sharing his magical knowledge with them.
Well, I haven't actually read this specific fanfiction, but generally speaking, it might involve Harry using his magic skills to combat the Chitauri. Maybe he'd use spells like Expelliarmus to disarm them or Protego to shield himself from their attacks. He could also team up with some of his wizard friends to take on the Chitauri threat.
Hermione would be a very likely ally. She's smart and resourceful, and could help Harry figure out the best ways to use magic against the Chitauri. Ron might also be there, with his loyalty and fighting skills. Additionally, some of the more experienced wizards or witches from Hogwarts could potentially join in to help Harry.
One way Harry could defeat the Chitauri is by using his knowledge of magical creatures. He might find a way to use a spell that affects the Chitauri in a similar way to how he would deal with a dark magical creature. For instance, if there's a spell that can paralyze a creature, he could modify it to work on the Chitauri. Also, his ability to communicate with magical beings might come in handy. Maybe he could find a way to communicate with some sort of alien magic (if it exists in the fanfic) and use it against the Chitauri. Another aspect is his friendship with his Hogwarts comrades. He could call on them for help, and together they could use combined spells to overpower the Chitauri forces.
Well, Spider Man would surely face a tough fight against the Chitauri. The Chitauri are a powerful alien force. But Spider Man has his own set of powers. He could use his spider - sense to anticipate their moves. He might also team up with other heroes in the fanfiction. Maybe Iron Man shows up and they combine their powers to defeat the Chitauri more effectively.
In this fanfiction, Iron Man could be one of his allies. Iron Man has the advanced technology and firepower to take on the Chitauri. They could combine their skills, with Spider Man's agility and Iron Man's powerful blasts. Another possible ally could be Captain America. His leadership and combat skills would be valuable in the fight against the Chitauri.
One common theme is the revelation of secrets. Often, Harry discovers something about Snape that makes him want to fight, like Snape's connection to the Dark Arts or some hidden actions he has taken against Harry or his friends.
Perhaps in this fanfic, Harry teams up with some of his Hogwarts friends. They combine their magical knowledge and courage. For example, Hermione could use her research skills to find a weakness of the Daleks, while Ron provides support and loyalty in the fight. And Harry, being the main hero, directly engages with the Daleks using his powerful spells like Expelliarmus but modified to have an effect on the Daleks' technology.
Maybe Harry discovers a hidden part of the wizarding world that uses guns as a form of magic - enhanced weaponry. So he has to learn how to use these guns in combination with his magic to defeat a powerful villain. For example, the guns could be enchanted to fire spells instead of normal bullets, and Harry has to master this new form of combat.