Typically, it emphasizes their unique personalities. Gumball is often portrayed as a bit of a goofball, while Nicole is more level - headed. Their love fanfiction plays on how these different traits interact. For instance, Gumball might do something silly to make Nicole laugh in the stories.
It's hard to say exactly without reading it, but generally in a crossover fanfiction like 'gumball the shell crossover fanfiction', it could be a creative exploration of how the worlds collide. For example, if 'Shell' has a certain type of magic system and 'Gumball' has its wacky family dynamics, the fanfiction might blend these. The characters from Gumball, like Gumball himself or Darwin, could find themselves in the 'Shell' world facing challenges that are a mix of both universes' typical problems.
There could be a 'dark gumball fanfiction' where Gumball is trapped in a nightmarish dimension and has to find a way out. In this story, his friends might seem different or be against him, adding to the dark and suspenseful nature. He has to rely on his wits and some hidden powers he discovers along the way.
One great female Gumball fanfiction could be about a female character from the show starting her own adventure in Elmore. Maybe she teams up with some of the minor characters and they go on a quest to find a lost treasure in the town.
You can try fanfiction websites like FanFiction.net or Archive of Our Own (AO3). These platforms usually have a wide variety of fan - created content, including Gumball fanfiction that might feature female characters.
Common themes often include love and friendship. Since they come from different 'families' in the show, there's also the theme of acceptance. How their families react to their relationship is also a popular theme. There can be stories about them facing difficulties together and growing closer as a result.
Perhaps a fanfiction where they get lost in a magical forest. They meet strange creatures and have to work together to find their way back home. Along the way, they learn more about their friendship and themselves.
One common theme could be the exploration of the relationship between Gumball and Marshall in a new and unique context. Since it's mpreg, there might be themes related to the challenges and joys of impending parenthood.
First, think of a unique and dark concept. For example, you could twist a normal Gumball situation into something really spooky. Then, develop your characters in a way that fits the dark theme. Gumball might become more cynical or desperate. Also, use descriptive language to set the mood, like 'The shadows in Elmore seemed to have a life of their own as Gumball walked home, his heart filled with dread.'