As I said before, without more context, it's difficult to determine who this Big Ed is. He could be anyone from a real - life individual to a fictional character.
The unique characters of Ed, Ed and Deets are what make the fanfiction interesting. Writers can explore their relationships in different ways, creating new storylines that might not be in the original source. It's exciting to see how different authors interpret these characters and the situations they can be put in.
You can try fanfiction platforms like Archive of Our Own (AO3). It has a vast collection of fanfictions from various fandoms. Just use the search bar and type in 'Ed, Ed and Deets' and it might show relevant stories. Another option could be Fanfiction.net, although the tagging system there might require some more precise searching.
One interesting railgun fanfiction could be one where the characters go on a new adventure outside of their usual Academy City setting. For example, they might end up in a parallel world where the rules of their powers are different.
To obtain the railgun in GTA 5 story mode, you might need to reach a specific level or progress through a particular storyline. Sometimes, it could also be hidden in a secret location that you need to discover.
In this volume, the story focuses on the characters' efforts to solve a complex scientific mystery while dealing with powerful adversaries. There are also some unexpected plot twists that keep you on the edge of your seat.