The plot could be about Ben using the Benfire form to save the world from a new, fire - based threat. Maybe there's a villain who can control all kinds of fire and is causing chaos, and only Ben in his Benfire form has the power to stop it.
Perhaps the Benfire form is a part of an ancient prophecy in the Ben 10 universe. Ben discovers this when he transforms into Benfire for the first time. The plot could then revolve around him fulfilling this prophecy. He has to go on a journey to different planets or dimensions to gather the necessary elements or allies to complete the prophecy's requirements, all while facing various obstacles and enemies who don't want the prophecy to be fulfilled.
In the context of a 'ben 10 benfire fanfic', it might explore the origin of this Benfire form. Is it something that Ben discovers accidentally? Or is it a form that has been hidden within his Omnitrix all along? The fanfic could also introduce new villains or challenges that are specifically related to this Benfire form, adding an exciting new dimension to the Ben 10 story world.
It could be about their adventures together. Maybe they go on a journey through a magical forest, facing various challenges like talking animals and enchanted obstacles.
The plot might involve Ben being captured by a new and powerful alien race. They could be interested in the Omnitrix technology. Ben would have to figure out their weaknesses while being held captive, and perhaps make some unexpected allies among the other captives. He'd then use his wits and the powers of the Omnitrix to break free and save the day.
One possible plot could be that Esther gets caught up in an alien conspiracy in the Omniverse. Ben, being the hero, steps in to save her. As they work together to uncover the truth behind the conspiracy, they start to fall for each other.
Well, in a 'Ben 10 Omniverse Ben x Kai' fanfic, perhaps it could start with Kai joining Ben on one of his inter - dimensional adventures. Along the way, they encounter various challenges that test their relationship. Ben might use his Omnitrix in creative ways to protect Kai, and in the process, they realize their mutual attraction. For example, when they are trapped in a strange alien world, Ben has to transform into different aliens to find a way out while also keeping Kai safe from the local dangers.
Well, it could be about Ben 10 being transformed into a girl and then having to deal with the differences in how society treats him/her. Maybe he/she has to face new challenges in using the Omnitrix while being a girl.
Maybe in the fanfic, Ben Tennyson is handcuffed as part of an experiment gone wrong. He has to figure out how to use his alien powers in a limited way with his hands cuffed. His struggle could be about not only getting free but also saving the day from the chaos the experiment created.
One possible plot could be that Ben, with his various alien forms, has to team up with Looma to save their respective planets from a common threat. Maybe a powerful intergalactic villain is on a rampage, and they have to combine their unique skills to stop it.
In this fanfic, perhaps the Avengers initially don't trust Ben because he's an unknown with such powerful and strange abilities. But then, when a common enemy attacks, like an alien race that wants to conquer Earth, Ben proves himself. He uses his different alien forms to complement the Avengers' skills. For example, using XLR8's speed to assist Quicksilver in a rescue mission. And throughout the story, they learn to work together and form a strong alliance.
A possible plot for a 'ben 10 catboy julia fanfic' could be that Julia is a new addition to Ben's group of friends. As a catboy, he has a natural curiosity that gets them into trouble. They stumble upon a mysterious place that seems to be connected to an ancient alien race. Inside, they find clues about a powerful weapon. But there are also traps and enemies. As they explore further, they learn more about Julia's past and how it's related to this place. Meanwhile, they have to fight off the bad guys who also want the weapon, using both Ben's alien forms and Julia's catboy abilities.