The Avengers as a whole would likely be outraged at the idea of someone being abused. Captain America would lead the charge in trying to bring the abusers to justice. The team would come together to not only protect the reader physically but also help them heal emotionally. They would surround the reader with love and support, showing them that there are good people in the world who will fight for them.
The Avengers' reaction would depend on how Eddie presents himself. If he comes in peace, some like Thor might be more open - minded. Thor has seen all sorts of strange creatures in the nine realms, so the symbiote might not seem too outlandish to him. However, Hulk might be more aggressive towards Eddie, seeing him as a potential threat to his 'family' (the Avengers).
Thor would be the most likely to relate to her on some level, as he comes from a world of gods and magic too. He might see her as an equal in a way. Bruce Banner would be interested in the scientific aspect of how her powers work, if there is any scientific explanation within the context of the fanfiction. And the others like Clint Barton and Wanda Maximoff would be curious about her background and how she ended up in their world.
Darcy would likely be both fascinated and a bit intimidated. When it comes to someone like Hulk, she might be a bit scared at first but then get really interested in the science behind his transformation. And for Iron Man, she'd be amazed at his high - tech gadgets and might start asking a million questions about how they work.
They would probably be very surprised. Some might laugh at the creative ideas in the fanfiction.
They would also be very protective. Tony Stark, for instance, would use his wealth and technology to give Harry a safe place to stay. Steve Rogers would offer his moral support and train Harry to be strong both physically and mentally. Natasha Romanoff would teach Harry self - defense skills. All of them would work together to make sure Harry never gets abused again.
Well, a lot could happen. Maybe the abused reader finds solace and protection among the Avengers. For example, if it's a story where the reader has superpowers but has been abused because of them, the Avengers could help the reader control and embrace those powers. They might offer a sense of family and belonging that the reader has never had before.
Hawkeye would be on high alert, remembering how Loki had mind - controlled him in the past. Bruce Banner would be a bit more reserved, worried that any sudden outburst of anger could bring out the Hulk. Loki, on his part, would be playing his own game, trying to see how he could fit into this new group dynamic. There would be a lot of tension and potential for growth in these character interactions.
Iron Man would be angry. He'd probably use his technology to try and track Percy down. He might also start to review all the security protocols to make sure no other traitors could do the same. Thor would be more of the 'let's fight him head - on' type, but the other Avengers would have to hold him back until they have a proper strategy.
The Avengers would initially be in shock when they find out Peter is sick. Clint Barton would be the one to keep a calm head and start organizing things. Wanda Maximoff would try to use her powers to ease Peter's pain if possible. Vision would use his vast knowledge to try and find a solution. They would all be very concerned and do everything they can to make Peter better, from getting the best medical help to providing a safe and comfortable environment for him to recover.
The Avengers might react in different ways. Steve Rogers would probably be polite but firm in getting to know Peter's boyfriend. He'd want to ensure that he was a good influence on Peter. Thor, on the other hand, might be a bit more boisterous. He could either be really friendly and enthusiastic, or his loud and powerful presence might accidentally scare the boyfriend a bit.