Some fanfics also focus on the psychological aspect of their relationship. Reiner and Bertholdt both have complex personalities and backstories. Fanfics might explore how they understand and support each other on a psychological level, perhaps dealing with their inner demons together.
Fanfiction.net is also a great place to look. There are many 'Attack on Titan' fanfics there. Just type in 'Reiner x Bertholdt' in the search bar and browse through the results. However, the quality may vary, so you might need to read a few to find the really good ones.
There could be various fanfictions. Maybe some that focus on alternative endings, like ones where certain characters survive who didn't in the original. For example, a fanfiction where Erwin survives and leads the Scouts in a different way.
One common theme is loyalty. Given their situation in the military and the secrets they hold, their loyalty to each other is often explored. Another is the theme of unspoken feelings. They both seem to have deep emotions that they don't easily express, and fanfics often play around with that.
One way is to check on popular fanfiction websites. Look for ones with high ratings and a lot of reviews. For example, Archive of Our Own (AO3) has a large collection of AOT fanfictions. You can search for the most popular ones there.
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.
The AOT manga has indeed come to an end. The story concluded with the last chapter, bringing closure to the series. However, fans' reactions to the ending have been quite diverse.