Kevin Levin is another popular character. His ability to absorb energy and matter makes for interesting interactions with the Omnitrix - powered characters. In fanfiction, he might befriend or oppose the Omnitrix user, and his complex personality always adds depth to the stories.
Ben Tennyson is of course one of the most popular. Since he is the original wielder of the Omnitrix in the canon, he often takes center stage in fanfiction. Fans love to write about his new adventures and how he continues to grow and develop his skills with the Omnitrix.
Naruto himself is often very popular. Since it's related to his world, fans like to see how he would interact with the Omnitrix and its powers. He could use it in his journey to become Hokage, or to protect his friends in new and exciting ways.
Well, obviously Ben Tennyson is a very popular character. He is the main character who wields the Omnitrix after all. His different alien forms like Four Arms or Heatblast are also quite prominent in the fanfiction world.
In some fanfictions, there might be female versions of some of the alien species that are popular in the Ben 10 universe. These female alien characters with their own Omnitrix - like devices could be popular. For example, a female Heatblast or a female Four Arms. Their unique abilities and personalities would attract readers, and the stories could explore how they use their powers in different situations compared to their male counterparts.
Well, Ben is obviously one of the main characters as the story is centered around him and the Omnitrix. Gwen might also be a main character as she often plays an important role in Ben's adventures, providing support or using her own magical abilities to help out. Grandpa Max could be another main character, offering his wisdom and experience to guide Ben through various situations.
Then there's Lyra. She's a female OC who is a brilliant scientist. She reverse - engineers some of the Omnitrix's functions and creates her own power - enhancing devices. She often teams up with other OCs and uses her intelligence along with the Omnitrix's powers to outwit their enemies.
Well, for example, Natsu's fire - dragon slayer magic could potentially interact with a heat - based alien form from the Omnitrix. Maybe when he's in that form, his fire magic becomes even more intense or has a different quality to it. He could use his dragon slayer skills to control the heat in a more precise way than the alien form normally allows.
Sasuke. He already has powerful Sharingan abilities. With the Omnitrix, he could add alien powers to his already formidable skills. He could use the speed of an alien form to enhance his own movement speed during battles and combine it with his Chidori attacks for even more devastating strikes.
Probably the main characters from the original work tend to be popular in fanfiction. They are well - known and have established personalities that writers can build on.
There could be original characters created specifically for the fanfiction. For example, a wizard who has some knowledge about the origin of the Omnitrix and tries to guide Harry. This character could be an old hermit - like wizard who has been studying interdimensional objects for years. Also, there might be a villain who is after the Omnitrix, someone who wants to use its power for evil purposes and constantly hunts Harry down.
Obviously, Naruto would be one of the main characters since he has the Omnitrix. But we could also expect to see his usual friends like Sasuke and Sakura. They would be involved as Naruto uses his new powers. And perhaps some of the alien forms from the Omnitrix could be considered 'characters' in a way, as they would influence Naruto's actions and decisions.