A great way to write this fanfiction is to explore the themes that both universes share. For example, the idea of survival is prominent in both the Twilight series and Gears of War. Have Bella and Marcus face challenges related to survival together. You can also add some conflict. It could be internal, like Marcus struggling with his feelings for Bella because he's so used to his military life, or external, such as facing a new enemy created from elements of both their worlds.
To write a good fanfiction, focus on character development. Show how Bella and Marcus would change as they interact with each other. Maybe Bella becomes more assertive under Marcus' influence, and Marcus becomes more in touch with his emotions because of Bella. Also, use vivid descriptions. Describe the settings, whether it's the dark and dangerous world of Marcus or the misty Forks of Bella's world. This will draw the readers in.
There could be a fanfiction where Marcus Fenix travels to Forks. He discovers the world of vampires and werewolves. Bella Swan is intrigued by his combat skills and they form an unlikely friendship. In this story, they might exchange their different survival skills, with Marcus teaching Bella about combat and Bella showing Marcus how to navigate the complex social hierarchies in Forks.
Use vivid descriptions. When Bella is thinking about staying or leaving, describe the world around her in detail. The sights, the sounds, the smells. It will make the readers feel like they are right there with her, experiencing the same emotions and dilemmas. Also, make sure to have good grammar and spelling to make your fanfiction more readable.
One great 'bella swan and marcus volturi fanfiction' is 'The Unlikely Bond'. In this story, Bella discovers a different side of Marcus that she never expected. Another one could be 'Marcus' Redemption'. It shows how Marcus tries to break free from the Volturi's dark ways because of Bella's influence. And 'A New Alliance' is also interesting, where Bella and Marcus form an unexpected alliance to face common threats in the vampire world.
One popular Marcus Fenix x OC fanfiction is 'A New Bond'. It beautifully weaves a story of an original character interacting with Marcus in the harsh world of the Gears of War setting. The OC in this story has a unique backstory that ties in well with Marcus's journey.
One popular Marcus Fenix crossover fanfiction might be the one where he crosses over with the Halo universe. In it, Marcus brings his unique combat skills and leadership to new and unexpected situations within the Halo setting.
One common theme is the clash of different worlds. For example, when Marcus Fenix crosses over into a different game or movie universe, there's always the struggle to adapt to new rules, cultures, and technologies. This can lead to some really interesting scenarios where he has to figure out how to use his skills in a completely new context.
One popular Marcus Volturi and Bella Swan fanfiction might be those where Marcus sees Bella's unique allure beyond the normal vampire - human dynamic. For example, in some stories, Marcus becomes her protector in the Volturi world, guiding her through the complex politics of the vampire clans.
One popular 'Bella Swan Marcus and Alistair mates fanfiction' is 'The Unlikely Bond'. It explores the unique relationships that form between them in an interesting way.
First, come up with a unique setting. It could be a post - apocalyptic world or a fantasy realm. Then, think about how Bella and Marcus will meet. Will it be a chance encounter or something more planned by fate? For example, they could meet at a magical marketplace.
The relationship in fanfiction can be very diverse. Some fanfictions portray it as a slow - burn romance. Marcus, being an ancient vampire, has a lot of past baggage, and Bella has her own issues with the vampire world. They start by having simple conversations, gradually getting to know each other better. In other stories, it's more of a friendship - based relationship. They might start to protect each other from the threats within the Volturi or from other vampires. And in some more creative fanfictions, their relationship is based on a shared spiritual or magical connection that is unique to them and helps them grow both as individuals and as a pair.