Mysterio would be an interesting villain for this fanfiction. He could use the chaos of the Age of Ultron to create illusions that further disrupt the city and make it difficult for Spider - Man to tell what's real and what's not. He might also be able to trick the Avengers into believing false threats, causing internal strife within the team.
Spider - Man could use his agility. He could quickly dodge Ultron's attacks and find a weak spot in Ultron's armor. Since he's so fast and nimble, he could get in close and plant some sort of disabling device he made with his scientific knowledge.
In some fanfictions, Ultron might team up with one of Spider - Man's villains, like the Green Goblin. They could create a plan to take over New York. Spider - Man would then have to face this powerful alliance. He might seek help from other superheroes he's associated with, like Iron Man or Daredevil, to combat this new threat.
Well, a fanfiction might explore Spider - Man's relationships within the Avengers during Age of Ultron. He's the new guy, so there could be some tension or bonding moments. For instance, he could have a heart - to - heart with Captain America about what it means to be a hero. Or he could have a friendly rivalry with Thor, competing to see who can take out more Ultron bots in a given time.
One great storyline could be Spider - Man trying to prove himself to the Avengers during the Age of Ultron chaos. He might start off as an underestimated newcomer but then show his true worth by using his unique abilities like his spider - sense to detect Ultron's minions before the others. Another could be a story where Spider - Man has to rescue a captured Avenger from Ultron, using his agility and web - slinging skills to outwit Ultron's defenses.
Spider - Man could fit in as an unexpected ally. He could be in New York when the chaos of the Age of Ultron starts spreading there. His knowledge of the city's layout and his ability to move quickly through it could be very useful. For example, he could help evacuate civilians while the Avengers are fighting the bigger battles against Ultron's forces.
The Green Goblin could be the villain. He could have developed a new type of pumpkin bomb that explodes with a force that seriously injures Spider Man. This would be in line with their long - standing rivalry in the Spider - Man universe.
How about a new villain created specifically for the fanfiction? A being made up of the combined negative energy from all the spider - verses. This entity could be called the 'Void - Spider' and it feeds on the chaos and destruction that often follows Spider - Man in his battles. It would be a very powerful and unique threat that the Spider - Men from different universes would have to face together.
Perhaps a new character, like a genetically - engineered super - soldier gone wrong. This villain could have super strength and agility similar to Spider - Man, but with a more aggressive and unpredictable nature. He might see Spider - Man as a rival and be determined to prove that he is the superior one in the city.
It could be a mad scientist who creates mutated creatures to cause chaos in the city.
Mysterio could also be a villain in this scenario. He could use his illusions to make the people of New York lose hope. Since Spider - Man has the Blue Lantern powers of hope, Mysterio would see him as a threat. He could create elaborate illusions that make it seem like the Blue Lanterns are a force of evil, causing chaos and making Spider - Man's job of spreading hope and protecting the city much more difficult.