In a Naruto - GTA 5 fanfiction, it could be interesting if the ninjas had to adapt to the technology in GTA 5. For instance, Naruto might be confused by guns at first but then learn to use them in combination with his kunai. Also, the concept of the tailed beasts could be related to some powerful and dangerous substances or artifacts in the GTA 5 world. Maybe the Nine - Tailed Fox's power is locked inside a secret military base in GTA 5, and Naruto has to break in to regain his power.
A possible plot is that a character from GTA, like Tommy Vercetti, finds a strange portal that leads to the Naruto universe. He enters and meets Naruto. Tommy is amazed by the chakra and ninja abilities. Naruto, on the other hand, is interested in Tommy's guns and modern ways. They decide to exchange knowledge. But then, a group of rogue ninjas and some GTA gangsters team up to stop them, thinking that their alliance will disrupt the balance of both worlds. Naruto and Tommy then have to fight against this combined force.
A crossover with the superhero genre could be really cool. Picture the GTA 5 protagonists meeting up with some superheroes. For example, Trevor might get into an argument with Deadpool over who's more crazy and unpredictable. And the GTA 5 characters could get superpowers for a short time and have to use them to save the city from a new threat.
A fanfiction could revolve around a lone player who discovers a hidden mystery within the GTA Online world. Maybe it's an ancient artifact that has special powers in the game, and they have to protect it from others who want to use it for evil.
The concept of using shadow clones in GTA - style heists is very creative. The clones can be used to distract the police or perform multiple tasks simultaneously during a robbery. Another creative idea is when the characters from Naruto have to deal with the moral ambiguity of the GTA world. For instance, Naruto, who is known for his strong sense of justice, has to navigate through the seedy underbelly of the GTA world, which often challenges his beliefs and values.
One idea could be that Amanda from GTA 5 somehow gets transported into the Naruto universe. She could be a powerful kunoichi due to her tough personality from GTA 5. Maybe she teams up with Naruto to fight against a common enemy. For example, an evil ninja clan that has plans to take over both the Naruto world and somehow invade the GTA 5 world too.
A plot could revolve around them starting a new business together. Since they both have different skills, Trevor's wild and fearless nature combined with Michael's more strategic thinking. They face challenges from competitors and have to figure out how to keep their business afloat while also dealing with their personal issues.
Perhaps the Orochimaru from Naruto is interested in the genetics and technology in GTA V. He tries to create new ninja - like beings using the resources and knowledge from the GTA V world. This causes chaos as his experiments start to run amok in both universes. The protagonists from both sides then have to work together to stop Orochimaru's mad plans.
One interesting idea could be the combination of Naruto's ninja skills with mecha technology. For example, Naruto might use his chakra to power up the mecha in unique ways. Another idea could be the new enemies that are created specifically for this mecha - Naruto concept, like robotic shinobi that require different combat strategies compared to normal foes. Also, the design of the mecha Naruto itself can be really cool, perhaps with features inspired by the Nine - Tails.
Yes, there are quite a few. Some fanfictions might combine the open - world chaos of GTA 5 with the ninja abilities and world of Naruto. For example, you could have Naruto characters in the GTA 5 city, using their jutsu to interact with the environment and other characters in the game world.
Another idea is that Aizen somehow ends up in the Naruto universe during the time of the Fourth Great Ninja War. He could try to manipulate both sides for his own gain. But Naruto, with his ability to see the good in people, might try to reason with Aizen and show him a different path. It could be a story of redemption or a great battle if Aizen refuses.