A third idea might be to focus on a time - skip in the Bloodstained Arc. Show how the world has changed, new technologies or magic have emerged, and how the characters have adapted or been left behind. This could also introduce a new generation of characters while still maintaining the essence of the original story.
Another plot idea could be a crossover within the Bloodstained Arc world. For example, two groups or characters that have never interacted before are forced to team up against a new, powerful enemy. This could lead to interesting character dynamics and development.
It could have intense battles and high stakes. Maybe characters face life-and-death situations and have to make tough choices.
One idea could be exploring a different backstory for Pain. Maybe he had a secret friendship with a Konoha ninja before turning to his dark path. This could add a new layer of complexity to his character and the conflict in the arc.
One idea could be to have Naruto characters enter the world of Yugioh Arc V and participate in duels. For example, Naruto could use his shadow clone jutsu in a creative way during a duel, like creating clones to confuse his opponent about which card he's actually playing. Another could be that the ninja world's chakra system somehow interacts with the Duel Monsters' energy in this fanfic world.
One idea could be that Jaune Arc discovers a lost dragon egg. When it hatches, a female dragon emerges. The dragon has unique powers that Jaune has to help her control. They form a bond as they face various threats in the world together.
One idea could be Boruto traveling back to the era of the First Hokage. He could witness the founding of Konoha and interact with the original founders. Maybe he tries to prevent a certain event that he knows will have long - term negative consequences in his own time.
Perhaps a mage who has been ostracized from their magical community due to their unorthodox methods. In the Bloodstained Arc fanfic, they could use their unique magic to either help or hinder the main events, depending on their motives.
One idea could be a crossover where characters from Naruto meet characters from Arc V. For example, Naruto could visit the world of Arc V and learn about their unique dueling system. Another idea is to focus on a side character from Naruto who gets transported to the Arc V universe and has to adapt to the new environment and rules. They could form unexpected alliances with the locals.
One idea could be an arc trooper crossing over into a modern - day Earth setting. Maybe he has to adapt to our technology and culture while also hiding his true identity. Another could be a crossover with a fantasy world, where the arc trooper's combat skills are put to the test against magical creatures.
One idea could be exploring new jutsu development within this arc. For example, Naruto might discover a jutsu that combines his Rasengan with a new element. Another could be the emergence of a new villain who has a unique connection to the concept of 'embodiment' in the Naruto world.
A possible plot could be that the arc troopers are sent to the Naruto world to retrieve a powerful and dangerous object. They end up having to work with the ninja there, like Sasuke and Naruto. There could be a lot of conflict at first due to different cultures and ways of fighting, but they gradually learn to trust each other and succeed in their mission.