Well, it could include the classic Evangelion characters like Shinji, Asuka, and Rei. They might be the ones dealing with the sudden appearance of Godzilla in their world. And of course, Godzilla himself would be a main 'character' in a sense, bringing his own set of behaviors and powers to the story.
It could be about Godzilla emerging in the world of Evangelion. Maybe the Angels in Evangelion are confused by this new giant monster. The Eva pilots might have to deal with both Angels and Godzilla at the same time.
Shinji would probably be terrified at first. He's already hesitant and scared in his normal battles, and Godzilla is much larger and more intimidating than the Angels he usually faces. Asuka would likely be more aggressive, thinking she can take on Godzilla with her Eva. Rei, on the other hand, would be very calm and observant, trying to understand Godzilla's nature. Misato would be in a panic initially, but then quickly start strategizing on how to deal with this new threat. Gendo would see Godzilla as either a new opportunity or a major obstacle depending on his long - term plans.
Well, in 'godzilla x evangelion fanfic', a cool concept might be the adaptation of Godzilla's regenerative abilities in the context of Evangelion. Imagine if an Evangelion unit could somehow gain that power. Also, the idea of the Nerv organization trying to study Godzilla's biology and use it to enhance their own mecha or combat strategies is quite fascinating.
Definitely the Eva pilots, Shinji, Asuka, and Rei. They are the main characters in Evangelion and would be at the forefront of dealing with Godzilla's appearance in their world.
One possible Pokemon Godzilla fanfic could be about a group of trainers who accidentally stumble upon a Godzilla - like Pokemon in a hidden, uncharted region. This Pokemon could have the immense power of Godzilla, causing chaos and also attracting the interest of both good and bad organizations within the Pokemon world. The trainers then have to decide whether to try and capture it or find a way to calm it down.
A possible plot idea is that Godzilla is drawn to the Geo - Front in Evangelion. The reason could be the powerful energy sources there. The NERV organization is then forced to either work with Godzilla or find a way to get rid of it. They might study Godzilla's biology to see if they can use any of its abilities to enhance the Evas. Another plot could be that an Angel takes on the form of Godzilla to deceive the Eva pilots. This would make the pilots question their usual tactics when facing an 'Angel' as Godzilla has different strengths and weaknesses compared to the normal Angels. Also, a plot where Godzilla's presence causes a shift in the power dynamics between the different factions in Evangelion, like SEELE and NERV, could be really interesting.
In general, the Evangelion mangas are considered good. They expand on the anime's universe, providing more depth and character development. However, it depends on personal preferences as some might find the style or pacing not to their liking.