Well, Eren Jaeger's transformation into the monster of the story is a complex process. He witnessed so much pain and suffering, especially the loss of his loved ones. This, combined with the power he gained, made him believe that only by using extreme force could he achieve his goals. He was no longer the naive boy he once was, but a force of destruction, ready to sacrifice countless lives for his vision of freedom, which ultimately made him seem like a monster in the eyes of many.
One consequence is the destruction of relationships. His friends who once trusted him are now conflicted. They have to decide whether to stop him or try to understand his motives. Another consequence is the chaos in the world. His actions as a'monster' have led to more wars and destruction.
Some fans are heartbroken. Eren is a very popular character, and his death can be a huge emotional blow. They might write comments expressing their sadness and disappointment.
Captain America would probably be very reflective. He might see his past self as a reminder of his long journey and how much he has changed. He could try to offer some words of wisdom to his younger self.
I'm not entirely sure as I haven't read it thoroughly. But generally, it might be about some kind of adventure in a fantasy world with unique characters and a complex plot.
Yes, there might be. The Naruto and Attack on Titan fandoms are both huge, and fans often like to cross over their favorite characters in fanfiction. So it's quite possible to find Eren - from Attack on Titan - in Naruto fanfiction. However, it may not be as common as fanfictions within each respective universe.
Definitely not. AOT is a work of fiction that combines elements of fantasy, action, and drama. It's set in a made-up world with its own unique plot and characters.
The AOT manga has finished. It wrapped up all the major plotlines and provided a conclusion to the story that fans have been following for a long time.