An OC could fit in by having useful skills. Like being good at hunting or knowing how to make weapons. That would make them valuable to the group in the fanfiction.
Well, it could be really interesting. The OC might bring in new skills or a different perspective. Maybe they'd be a great fighter and help the group survive better, or perhaps they'd have some knowledge about a potential safe haven that no one else knew about.
It could be terrifying. They might find themselves in a post - apocalyptic world full of zombies. They'd have to quickly learn survival skills like finding food, shelter, and weapons. And they'd also need to figure out how to deal with the other survivors, some of whom could be dangerous.
A really interesting plot could be a character being transported into the game right at the moment when a major decision has to be made by one of the main characters in the game. The transported character tries to influence that decision, which has far - reaching consequences for the whole game world. They might have knowledge from playing the game that they think can save more lives, but things don't always go as planned in the chaotic world of The Walking Dead game.
I think a scientist would be really interesting. They could potentially use their knowledge to find a cure for the zombie virus within the game world. They might start by analyzing the infected and trying to figure out how the virus works.
Survival is a very common theme. Since it's set in the post - apocalyptic world of 'The Walking Dead', OCs are often trying to find ways to stay alive, whether it's from walkers or other dangerous humans.
Since it's an OC fanfiction, the main character is likely the Original Character who is immune. But there could also be other characters from the Walking Dead universe that interact with the OC. Maybe Daryl, who is known for his survival skills, could be involved. He might be initially skeptical of the OC's immunity but later come to rely on it.
One interesting storyline could be an OC (Original Character) who has a unique survival skill like being able to quickly build hidden shelters. This OC might use their skill to protect a group of survivors from a horde of walkers. Another could be an OC with a medical background who tries to find a cure for the zombie virus within the world of The Walking Dead.