One common theme is power exploration. Since Rimuru has unique powers in the original series, many fanfictions explore different aspects of his powers or even give him new powers. Another theme is relationship building. Rimuru's relationships with his various friends and allies are often expanded upon in fanfiction.
The unique concept of being reincarnated as a slime is really interesting. It allows for a fresh take on the isekai genre. Also, the way the slime, Rimuru, builds his own community and kingdom is engaging.
Veldora is another favorite. His power and his somewhat comical yet powerful nature make him interesting in fanfiction. There could be stories where he takes on a more mentoring role to Rimuru or gets involved in unexpected adventures.
Rimuru starts as a rather weak slime, but as the story progresses, he evolves through various means. He absorbs knowledge from the beings he assimilates, which broadens his understanding of the world. His experiences with forming alliances, resolving conflicts, and building his own territory contribute to his growth. He becomes more confident, more strategic, and more empathetic towards others, which are all signs of his remarkable growth throughout the novel.
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.
There is a fanfiction called 'Rimuru's Ascent'. It shows Rimuru's journey towards an even higher level of power and how he overcomes various challenges on the way. The story also includes some unique magical concepts that add to the overall allure. Additionally, 'Rimuru and the Lost Realm' is a fanfiction where Rimuru discovers a mysterious realm that was previously unknown, full of strange creatures and new opportunities for growth.
Another concept could be the development of new skills or abilities for Rimuru, the main character. Fanfiction might come up with really creative powers for him, like the ability to transform into different elemental forms that are not in the original story. This can add a whole new layer of excitement to the adventures.
Well, in this fanfiction, there could be new storylines centered around the slime's attempts to introduce modern - day ideas to the medieval - like world it's in. This includes things like new forms of governance or economic systems. Also, the exploration of how the slime's non - human form affects its perception of the world and morality is quite fascinating.
The main character is Rimuru Tempest. He was originally a human who got reincarnated as a slime in another world. There's also Veldora, the powerful dragon that Rimuru befriends early on. Shion is another important character, a strong ogre who becomes one of Rimuru's loyal followers.
I really like 'The Slime's New Adventure'. In this fanfic, Rimuru discovers a whole new continent filled with different races and magic. It's full of action and adventure, with Rimuru having to face powerful enemies and make new allies. The writing style is engaging and easy to follow.