One idea could be a crossover where Naruto meets Barbatos in a strange dimension. Naruto could be intrigued by Barbatos' powers and they could team up to fight a common enemy. Maybe a powerful demon that threatens both their worlds.
It could start with Naruto being mysteriously summoned to a strange world where he sees the Gundam Barbatos for the first time. He's confused but quickly realizes the power of this huge machine.
It could be a really cool story where Naruto's ninja skills are combined with the power of Gundam Barbatos. Maybe Naruto could use his chakra to enhance the Gundam's abilities, like making its attacks faster or stronger. For example, he could infuse his Rasengan with the Gundam's weapon systems.
Start with a strong premise. For example, a prophecy that only Naruto and Barbatos together can fulfill. Then build up the conflict, like having an evil force trying to stop them from achieving the prophecy. This will keep the readers engaged.
Since this is a made - up title for the purpose of this question, we can only assume that Rex is likely a character in the Star Wars universe. He could be a clone trooper, as there are many clone troopers named in the Star Wars franchise. Or he could be a new, original character created specifically for this 'story' who might be a smuggler, a rebel, or even a Jedi in hiding.
Rex was originally a police dog trained for special tasks. His background involves various experiences that shaped his skills and instincts for solving crimes.
In a post - apocalyptic world, Generator Rex was on a mission. Rex was also exploring the same area. They both heard rumors of the Black Knight. When they finally met the Black Knight, he was not what they expected. The Black Knight had a code of honor. Rex was intrigued and Generator Rex was curious about his technology. They started to exchange knowledge. The Black Knight taught them some ancient combat techniques and in return, Generator Rex shared his knowledge of advanced machinery. Rex learned a lot from both of them and they became friends, vowing to protect the world together.
There were novels similar to Legend of Rex:
1." Longevity Begins from the Forbidden Art," Author: Super Erha
The following is a detailed introduction of these novels:
1." Longevity begins with the extraction of forbidden techniques ": Reincarnated into a high-level martial arts world, Chen Xuan activates the forbidden technique system and is exempted from the price of the forbidden technique.
Faced with the cruel situation, he had to extract forbidden techniques and open the path of crushing forbidden techniques!
Permanently forbidden technique, Ten Times Longevity Burning Saber Technique. The power of each slash was multiplied by ten times. The ultimate move was a normal attack!
One-time use forbidden technique, Eight Gates, Ye Kai. Who could block this kick of Ye Kai!
As he smoked, Chen Xuan realized that there was no one else who could stand shoulder to shoulder with him. He was the only one in the world!
You can read these novels on Qidian Chinese Network.
One possible fanfiction could be about Rex's adventures in a new, uncharted area where he discovers a strange new type of E.V.O. He has to use his powers in creative ways to deal with it and learn more about this new threat or ally.
Naruto might try to befriend the Indominus Rex. He's always been one to see the good in others, even enemies. So he'd probably approach it with an open heart. Sasuke, on the other hand, would be more cautious and likely see it as a threat to be eliminated if necessary.