One interesting plot could be that Beppi and Djimmi team up to put on a spectacular circus - magic show in the Cuphead world. They combine Beppi's circus skills like his wild animal taming with Djimmi's magic to create a show that amazes all the other characters.
One common theme could be friendship. Since they are two characters, their relationship might be explored in terms of how they become friends or how their friendship evolves.
One idea could be that they team up to create a magical circus performance. Beppi brings his fun and wacky carnival elements while Djimmi adds his magical touch. Another could be a story where they have a friendly competition to see who can bring more joy to the people in their world. They might start with small contests like who can make the best balloon animals or create the most dazzling light show.
Well, clearly the main characters are Beppi the Clown and Djimmi the Great. Beppi is known for his zany circus antics and Djimmi for his powerful magic.
One plot idea could be Djimmi and Beppi teaming up against Cuphead. They might create a series of wacky challenges in their own magical and carnival - themed worlds respectively, and Cuphead has to go through them to get a special item. Another idea is a story where Djimmi and Beppi start as rivals, each trying to outdo the other in terms of magic tricks or carnival attractions, but then they realize they can be more powerful together.
I'm not sure of specific djimmi x beppi fanfiction off the top of my head. You could try searching on fanfiction websites like Archive of Our Own. There might be some interesting stories there.
A jealous carnival owner could be the antagonist. He doesn't like Beppi teaming up with Djimmi because he fears their combined popularity will overshadow his own carnival. So he tries to sabotage their shows and separate them.
Djimmi would be really interesting. As a genie, he has a lot of magic powers and a whole magical realm to explore. His character is full of mystery, and his motives can be very complex. You could explore his backstory, like how he became a genie, and what his true desires are. There could be a story about him trying to break free from the constraints of being a genie, and Beppi could be the catalyst for this change, either helping or hindering him.
There could be a plot where a human is cursed by an evil witch, and a good witch decides to help the human break the curse. Along the way, they form a deep bond. The human learns about the witch's world, and the witch learns about human emotions like love and friendship, which in the end, is the key to breaking the curse.
One interesting plot could be Naruto and Nora teaming up to face a powerful new enemy that neither of their worlds has seen before. They combine their unique skills, like Naruto's shadow clones and Nora's hammer - wielding abilities, to take on this threat.
One interesting plot could be Mito and Naruto teaming up to face a new and powerful enemy in the Hidden Leaf. Maybe an ancient evil that only their combined powers can defeat.