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.
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.
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.
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.
Well, it could be that Harry is facing some new dark forces in the fanfiction. Maybe he discovers a hidden group of dark wizards who are plotting against Hogwarts, and he decides to fight back to protect his school and friends.
In a 'Harry Fights Alone' fanfiction, the plot could involve Harry being betrayed by his friends. Maybe they are put under a spell that makes them turn against him. Harry then has to face the dark forces all by himself. He might have to rely on his own wits and the few spells he has mastered alone. For example, he could be in a situation where he has to battle Voldemort's minions without Ron and Hermione to back him up, and he discovers new powers within himself during this struggle.
The fanfiction could start with Harry being magically transported to Kaguya's world. He'd be confused at first but quickly realize he has to fight to survive. Harry's wand would be his main weapon. He might learn some new spells during the fight, perhaps a spell that can nullify Kaguya's ability to freeze time. As the fight progresses, both characters would start to respect each other's power, leading to an unexpected alliance at the end.
Perhaps in this fanfiction, the court in the wizarding world has been corrupted. Harry discovers some dark secrets within the court system. He then decides to fight against it to bring justice. He might start by gathering evidence against those who are misusing their power in the court.
Well, perhaps Teddy is in some sort of danger. Maybe he's being targeted by dark wizards because of his connection to Harry. Harry, being the heroic type, decides to fight to protect Teddy. He could use his magic skills and the support of his friends like Hermione and Ron to keep Teddy safe.
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.