One plot idea could be Naruto unknowingly awakening the power of the Demon God within him during a particularly intense battle. This new power could be both a curse and a blessing as he struggles to control it while also using it to protect his village.
Maybe the Demon God was sealed away long ago by the first Hokage, and Naruto discovers a way to communicate with it. They form an unlikely alliance where Naruto tries to change the Demon God's malevolent nature in exchange for its power to defeat a new, powerful enemy threatening the ninja world.
Maybe there's an ancient prophecy in the 'naruto half demon half god fanfiction' world that Naruto is the key to saving the world because of his half - demon half - god heritage. But he first has to unlock all of his powers. This would lead to a journey of self - discovery, where he meets different characters who help or hinder his progress. Along the way, he could also learn about the origin of his unique nature and how it came to be.
Perhaps the Shark Demon is a cursed being, and Naruto, with his big - hearted nature, tries to break the curse. He discovers that the curse was placed by an ancient evil ninja. Naruto then embarks on a journey to find a way to break the curse, with the Shark Demon reluctantly following him at first, but eventually becoming a true friend.
A really interesting plot could be that Naruto, as a demon, is wrongly accused of a series of attacks in the ninja world. He has to prove his innocence while also dealing with the prejudice and fear that his demon form instills in others. He might have to discover a way to temporarily suppress his demon form to gain the trust of those around him.
Perhaps in the fanfiction, God Naruto discovers a hidden realm where Kushina is trapped. He has to overcome various challenges and trials in this realm to rescue her. Once they are reunited, they could work together to bring about a new era of peace and prosperity in the ninja world. It could also be interesting if God Naruto shares his godly powers with Kushina, making her an even more formidable ninja.
Well, a possible plot could be that Naruto, as a god, decides to teach the next generation of ninjas in a completely new way. He might introduce them to powers and techniques that were previously unknown. For example, he could show them how to manipulate energy on a cosmic level. Also, he could be in a situation where other gods from different realms see him as a threat and try to take his powers away.
One idea could be Naruto getting trapped in the demon world and having to form alliances with different demon clans to find his way back. He could learn unique demon jutsus during his time there.
Well, perhaps Demon Naruto has some sort of special connection to Kushina that is related to his demonic powers. For example, her Uzumaki bloodline might be the key to controlling or understanding his demonic side better. And they could go on a journey to discover the secrets of his powers together.
One idea could be that the demon prince has a hidden power that only Naruto can unlock. This power could be related to an ancient prophecy. Another could be that the demon prince is actually a misunderstood being and Naruto is the first to see his true nature. Maybe they team up to fight a common enemy that threatens both the human and demon worlds.
One idea could be that the demon overlord has a hidden past with Naruto's family. Maybe he was once an ally but was betrayed, and now he's back for revenge while Naruto tries to understand the truth.
One plot idea could be that the Demon Queen is initially an enemy but Naruto, with his talk - no - jutsu, tries to understand her motives. Maybe she has a tragic past that led her to be a 'demon queen' and Naruto wants to help her change. Another could be that they are forced to team up against a greater evil that threatens both the ninja world and the demon realm. For example, an ancient dark force that wants to enslave both humans and demons.