The Misty fanfic might also focus on her role in specific missions in Black Ops 2. For example, it could describe in detail her actions during a crucial battle, how she strategized, and interacted with her teammates. It could be a really exciting way to expand on her character in the game's universe.
You can expect action-packed scenes in a Misty fanfic. Since it's based on a Call of Duty game, there will likely be a lot of combat situations and high - stakes moments.
To develop their characters further, Marlton could be shown to overcome his fears more often. For example, if he has a fear of heights, put him in a situation where he has to climb a tall building to complete a mission. Misty could be developed by exploring her past more. Maybe she has a family she left behind, and that could be a motivation for her actions. They could also be developed through their interactions with each other. If Marlton is usually shy, Misty could help him become more confident, and vice versa.
One plot idea could be Marlton and Misty getting separated from the rest of the group during a mission. They have to rely on each other to survive in a hostile environment. Maybe they discover a hidden enemy base while trying to find their way back. Another idea is that they find an ancient artifact that has some sort of power, and they must figure out how to use it to their advantage. A third plot could involve them having to deal with a traitor within their own ranks who is trying to undermine their mission while they also deal with their growing relationship.
The story of Black Ops 3 is somewhat related to Black Ops 2. Some storylines and events carry over or have references that link the two. But it's not a direct continuation; there are new elements and developments too.
The story of Black Ops 4 is separate from Black Ops 3. They have different settings, characters, and plotlines. Although they belong to the same franchise, the narratives are independent of each other.
Black Ops 3's storyline takes place in a chaotic world. Players encounter high-tech enemies and have to uncover hidden secrets to save the day. It's full of surprises and challenges.