One idea could be that Ben Tennyson somehow gets transported to the Fairy Tail world. He could team up with Natsu and the gang to fight a common enemy that has the power to absorb alien DNA like Ben's. They would combine their different powers and fighting styles to take on this new threat.
A more complex idea could be that the magic in the Fairy Tail universe somehow affects the Omnitrix, causing it to mutate and create new and unexpected alien forms. This would bring in elements of both worlds in a very unique way, and the characters would have to figure out how to deal with these new forms and the potential threats or benefits they bring.
Ben Tennyson himself is a great choice. His ability to transform into different aliens offers a lot of potential for interesting interactions with the magic of Fairy Tail. For example, how would his Heatblast form interact with a fire - using mage from Fairy Tail? It could be a really cool dynamic.
A pairing between Ben and Lucy could also be fascinating. Lucy is a Celestial Spirit Mage, and she has a more strategic approach compared to some of the other Fairy Tail members. Ben could protect Lucy while she summons her spirits, and in return, Lucy could use her magic to help Ben when he's in a tough spot in his alien forms. Their different powers and personalities would create a lot of interesting interactions in the fanfic.
One possible plotline is that Ben Tennyson accidentally gets transported to the world of Fairy Tail. He has to figure out how to use his Omnitrix in a world full of magic. Another could be that the Fairy Tail guild discovers an alien device similar to the Omnitrix and they try to figure out how it works.
One possible plot could be that Ben Tennyson somehow ends up in the world of Fairy Tail. He could team up with Natsu and his friends to fight against a common enemy. Ben could use his alien forms to combat the dark magic threats that Fairy Tail often faces.
Sure. You can start by looking on fanfiction.net. There are often many creative crossovers there. Some might focus on the characters from Ben 10 having to adapt to the magic - filled world of Fairy Tail, while others could be about Fairy Tail members getting their hands on the Omnitrix.
Well, in Ben 10 vs Fairy Tail fanfic, a really interesting crossover is when the power - up systems cross over. Imagine Ben 10's Omnitrix getting a magical upgrade from Fairy Tail's magic. Or the Fairy Tail mages getting some alien - like powers from Ben 10. Also, the cultural exchange between the two universes can be fascinating. Ben 10's modern - day Earth background compared to Fairy Tail's more medieval - like fantasy world can create some really unique storylines when they interact.
Well, an unlikely alliance in this fanfiction could be between Ben and Natsu. Natsu is all about fire and brute force, while Ben has his various alien forms with different abilities. They could initially clash due to their different approaches to fighting, but then realize that together they can be much stronger. For instance, if Ben transforms into an alien with wind - based powers, he could enhance Natsu's fire attacks.
One great idea for a Ben 10 and Fairy Tail fanfiction could be a story where Ben uses his Omnitrix to transform into an alien that has a power similar to a Fairy Tail magic. For example, he could transform into an alien with ice - based powers like Gray's magic in Fairy Tail. This would create an interesting dynamic as he teams up with the Fairy Tail guild members to fight a common enemy.