One idea could be exploring new Grimm species that exist in deep space. Another could be the characters from RWBY getting stranded on a strange, uncharted planet in deep space and having to adapt to survive. Maybe they discover a long - lost civilization in space with its own unique Dust - like energy source.
Well, you could have an OC who is an alien with special powers that are different from the normal Semblances in RWBY. For example, they can control gravity in a way that gives them an edge in combat. Or an OC that is a diplomat from a space - faring civilization trying to make peace between different kingdoms on Remnant. Also, an OC who was stranded on Remnant after their spaceship crashed and has to adapt to the world while also trying to find a way back home.
One idea could be a fanfic that explores the backstories of minor characters in RWBY more deeply. For example, you could focus on a character like Velvet and create a story about her training before coming to Beacon. Another could be a crossover within the RWBY universe itself, like a team-up between different schools' teams that we haven't seen much of in the official series.
Well, a great Naruto space fanfic could involve Naruto going on a quest in space to find a rare chakra - enhancing crystal that only exists on a far - off planet. Along the way, he meets new allies who are also from different planets and have their own unique powers. He has to combine his ninja skills with their alien abilities to overcome obstacles.
One idea could be to explore an alternate origin for the characters. For example, what if Ruby's silver eyes were a result of a prototype experiment gone wrong? Another could be to set the fanfic in a parallel universe where the Grimm are actually created by a mad scientist using prototype technology. And perhaps a story where the characters have to use prototype weapons that have unpredictable powers.
One idea could be exploring new stand abilities inspired by RWBY characters' weapons or semblances. For example, a stand based on Ruby's Crescent Rose could have the ability to manipulate time briefly like Ruby can move at high speeds. Another idea is to create crossovers within the RWBY universe using stands, such as having a stand user from a different part of Remnant interact with the main RWBY team and their battles.
For a 'rwby breeding fanfic', you might look at the idea of cross - species breeding if there are non - human characters in RWBY. Maybe a Faunus character breeds with a human - like character. This could bring up all sorts of interesting cultural and physical differences in the offspring. The fanfic could explore how the society in RWBY reacts to such cross - breeding, whether there is acceptance or discrimination, and how the characters themselves deal with the consequences of their actions.
You could base the fanfic on a quest. The RWBY team is hired by a DND - like noble to retrieve a powerful artifact. This artifact could be something that has the power to change the balance in Remnant (the RWBY world). Along the way, they encounter classic DND monsters like dragons and beholders. They also meet different DND races, such as elves and dwarves, and have to form alliances. Ruby might be the leader in this quest, using her quick thinking and charisma, while Weiss uses her knowledge of magic and lore to figure out clues.
One idea could be exploring the backstories of minor characters in more depth. For example, you could focus on a character like Velvet and her experiences at Beacon Academy before the main events of RWBY. Another idea is to create an alternate universe where the Dust technology has different properties or uses. Maybe in this AU, Dust can be used to create temporary portals to different locations.
A prequel could center around the formation of the different kingdoms. Explore the political tensions and alliances that were made. You could also show how the Dust was discovered and how it became such an important resource. This would give readers a better understanding of the world of RWBY before the events of the main series.
Well, you could do a crossover where the Danganronpa students are transported to the RWBY world. They'd have to adapt to the Grimm and the Huntsman - Huntress system. Or perhaps create a scenario where the two universes are merged, and there are new rules for survival. The characters from both series would have to form alliances based on their skills and personalities.