A really unique plot could be a situation where the tailed beasts in Naruto are related to the powerful demons in Inuyasha. For instance, the Nine - Tailed Fox could have a connection to a major demon in Inuyasha's world. This discovery could lead to a journey where Naruto has to travel through the Inuyasha world with Inuyasha and Kagome to find out the truth about this connection and how it can help or harm their respective worlds.
A cool plot could be that there's a tournament across different anime worlds, and Inuyasha and Naruto are chosen to represent their respective worlds. Along the way, they discover similarities in their pasts, like both having some form of demon - related heritage (Naruto with the Nine - Tails and Inuyasha being a half - demon). They also exchange combat techniques. Naruto teaches Inuyasha how to better use chakra control in his attacks, and Inuyasha shows Naruto some unique sword - fighting skills.
One plot idea could be that Naruto and Inuyasha are somehow transported to a new world where they encounter a group of unique female characters. They have to work together to survive and in the process, a harem situation starts to develop as the girls are attracted to their different qualities. Naruto's determination and Inuyasha's rough - edged charm draw the ladies in.
One interesting plot idea could be that Naruto somehow gets transported to the Inuyasha world. He teams up with Inuyasha and they have to face a common enemy, like a powerful demon that is threatening both the ninja world and the feudal Japan world. Naruto's unique jutsu combined with Inuyasha's sword skills would make for some epic battles.
A possible plot could involve the Hollows from Bleach somehow making their way into the Inuyasha universe. Inuyasha and his friends would have to team up with Ichigo and the Soul Reapers to fight them. This would create a really interesting dynamic as the different fighting styles and powers collide. The Hollows might also target the demons in Inuyasha's world, seeing them as a new source of power or prey.
One idea could be that Inuyasha gets transported to the Ouran High School world. He'd be this wild and rough - around - the - edges character in a posh, refined school setting. Maybe he mistakes the Host Club for some sort of demon - like group at first and tries to fight them. Another plot could involve a character from Ouran getting dragged into Inuyasha's feudal Japan world and having to adapt to the lack of modern conveniences and the presence of demons.
Well, a cool plot for this crossover fanfiction could be that the Pokemon trainers are summoned to the Inuyasha world to help stop a new evil that is related to both the Pokemon world and the Inuyasha world. Maybe a villain has found a way to combine the power of the Shikon Jewel with a powerful Pokemon artifact. The trainers and their Pokemon have to work together with Inuyasha and his friends. Some Pokemon might evolve during the intense battles, and the Inuyasha characters could learn about the concept of evolution in the Pokemon world, which could be a fun aspect to explore.
Perhaps there could be a common enemy that both Inuyasha and Naruto have to face. A powerful demon or a rogue ninja who has found a way to travel between their worlds. They would have to combine their unique skillsets, like Inuyasha's speed and strength along with Naruto's Rasengan and his ability to inspire others. Their friends would also play important roles, like Sakura helping with medical needs and Kagome providing spiritual support.
One idea could be an Inuyasha and Naruto crossover. Picture Inuyasha in the Hidden Leaf Village, his sword skills and demon powers causing quite a stir among the ninja. Another could be a crossover with Harry Potter. Inuyasha at Hogwarts, trying to figure out magic while also dealing with his own demon - slaying business. Maybe he'd have some interesting interactions with the magical creatures there.
One idea could be that Inuyasha's Tessaiga and Zatch's spell book somehow get switched. This would lead to Inuyasha trying to figure out how to use Zatch's magic while Zatch has to deal with a powerful and strange sword. Another plot could involve a common enemy that forces Inuyasha and Zatch to team up. Maybe a demon from Inuyasha's world has found a way to cross over into Zatch's world and is causing chaos, and only by combining their powers can they stop it. A third plot could be a more comical one where Inuyasha and Zatch meet by accident and at first think the other is an enemy but then slowly become friends through misunderstandings and shared adventures.
Maybe there could be a dark force that is threatening both the Inuyasha world and the Sailor Moon world. So, Sailor Moon and her Sailor Guardians team up with Inuyasha, Kagome, and the others. They could combine their powers in unique ways. For example, Sailor Moon's healing powers could be used on Inuyasha when he gets seriously injured in a fight against the common enemy, and Inuyasha's strength could be used to protect the Sailor Guardians from some of the more physical threats in his world.