One idea could be the main character exploring a new, hidden part of the slime world that has unique magic and creatures. For example, a place filled with sentient plants that can communicate with slimes.
A plot could involve the slime protagonist forming an alliance with a group of normally hostile monsters through a series of unexpected events. Maybe they start by accidentally saving the life of a powerful monster's young, which then leads to a complex relationship and cooperation. This could bring a whole new dynamic to the slime's journey in this world.
One idea could be the slime exploring a new, uncharted part of the fantasy world. Maybe it discovers a hidden civilization of magical creatures that have unique powers and a different social structure. Another plot could involve the slime forming an alliance with a powerful but misunderstood monster against a common enemy, like an evil wizard who wants to enslave all non - humanoid beings.
One interesting plot idea could be the slime exploring new and uncharted territories in the fantasy world. Maybe it discovers a hidden civilization of magical beings that no one else knew about.
Maybe an OC that is a hybrid of two different races in the 'That Time I Got Reincarnated as a Slime' universe. This OC could struggle with acceptance from both races and have to find their place. They could use their mixed heritage to develop a new form of combat or magic that is unique to them, making them a valuable asset to Rimuru's group.
One interesting plot could be Naruto having to adjust to his new slime form. For example, he might struggle with not having hands in the traditional sense at first but then discovers unique ways of using his slime body for combat or daily tasks. Another plot could be Naruto using his ninja knowledge in the slime world. He could teach the slimes some of his ninja techniques, like how to move stealthily or use basic chakra concepts in their own slime - based magic system.
Perhaps the reincarnated character has a special ability that allows them to communicate with the unique monsters in the Tensura world. This ability could lead to forming alliances that no one else could, and they could use these to their advantage to gain power and protect the world from new threats.
One idea could be that the reincarnated character has knowledge of future events in the Naruto world. For example, they know about the Akatsuki's true intentions from the start and can start preparing the Hidden Leaf Village earlier. Another plot could be that they have a special power from their past life that no one in the Naruto world has seen before, like the ability to control modern technology within the ninja world. A third idea is that they are reincarnated as a side character and their actions end up changing the entire course of the original Naruto story in unexpected ways.
One idea could be that the reincarnated character has memories of the future of the Boruto world. So they try to prevent certain disasters from happening, like the fall of Konoha. Another could be that they use their modern - day knowledge to revolutionize the ninja technology in the Boruto universe.
One idea could be that the reincarnated character has knowledge of future events in the Danmachi world. For example, they know about certain monsters' weaknesses or hidden treasures. This could give them an edge as they navigate the dungeon. Another could be that they are reincarnated as a non - human race in the Danmachi world, like a spirit or a dwarf, and they have to deal with the different cultural and physical aspects of that race. A third idea is that the character reincarnates with a special ability that doesn't exist in the normal Danmachi world, like the power to control time on a small scale, which would completely change their adventures in the dungeon.
One idea could be that the protagonist, reincarnated as a dinosaur, tries to prevent the extinction event. They could use their human knowledge to find a way to survive the impending asteroid or environmental changes.
A third plot idea could be the relationship between the sword and the other characters. Since it's reincarnated as a sword, it can't communicate in the traditional sense. So, how it forms bonds with the people around it, like the protagonist who might be the one it eventually chooses as its wielder. It could be through dreams or visions that it imparts knowledge or feelings to the characters, creating a unique and complex relationship dynamic.