Perhaps a plot where the members of the Ten Commandments are sent to the world of the Seven Deadly Sins in an amnesiac state. The Sins then have to figure out what has happened to these powerful foes. As they try to help the Ten Commandments regain their memories, they start to form unexpected bonds. For instance, Ban could form a friendship with Estarossa as they both have a connection to immortality in different ways. This could lead to a complex web of relationships and power dynamics that are different from the usual conflict - based interactions between the two groups.
A plot where a magic spell goes wrong and the powers of the Seven Deadly Sins and the Ten Commandments get swapped randomly among their members. This would lead to chaos as they have to adjust to new abilities and powers while also dealing with the fact that their enemies might now have an edge over them. The Sins would have to quickly adapt to the Commandments' powers and vice versa. It would be a fun exploration of how different characters handle new powers and how they strategize in battles with this new dynamic.
Meliodas and Zeldris would be very likely to have an interesting interaction. They are brothers with a complex history. In a crossover, their relationship could be explored further. Maybe they start off on opposite sides as per their respective groups, the Seven Deadly Sins and the Ten Commandments, but then find common ground due to their family ties. Another pair could be Ban and Estarossa. Ban's quest for immortality and Estarossa's power - related to immortality in some way - could lead to some intense and thought - provoking conversations and battles between them.
A cool plot could be that there is a mysterious tournament that somehow bridges the two worlds. Duelists from Yu - Gi - Oh GX and Yu - Gi - Oh 5DS are invited to participate. However, it's not a normal tournament as there are strange rules and hidden agendas. The GX characters, like Jaden, bring their fun - loving and sometimes unpredictable dueling styles, while the 5DS characters, such as Yusei, bring their more strategic and high - speed dueling approaches. As the tournament progresses, they start to uncover the truth behind it and have to work together to stop those who are misusing the tournament for evil purposes.
One possible plot could be that Naruto and his friends from the Naruto universe somehow get transported to the world of Yugioh 5ds. There, they discover the power of Duel Monsters. Naruto might be intrigued by the strategic battles and could try to learn how to duel. Maybe they team up with Yusei and his crew to face a common enemy that threatens both worlds, like an evil organization that wants to use the chakra and Duel Monsters energy for their own dark purposes.
Well, perhaps the story could start with a strange distortion in the Metaverse that links the two universes. Some of the characters from Persona 4 start having dreams about the events in Persona 5's Tokyo, and vice versa. This leads to a meeting between the two groups. They then discover that an ancient evil, long forgotten in both their histories, is trying to use the connection between the two worlds to gain enough power to rule over everything. The characters would have to learn about each other's powers and personalities quickly in order to stand a chance against this new foe.
One possible plot could be that Doflamingo somehow ends up in the RWBY world. He might initially try to take over, using his strings to manipulate the Grimm. But the RWBY team discovers his true nature and battles him. Ruby could use her speed to avoid his string attacks while Weiss uses her glyphs to counter his powers.
Well, perhaps Bowser somehow makes a deal with some of the more malevolent characters in the Undertale world, like Flowey. Then Mario has to not only deal with Bowser but also the new threats from the Undertale realm. He might have to learn about the concept of LOVE and EXP in the Undertale world to fully understand how to defeat his enemies. And along the way, he could meet Sans and Papyrus, and they could have some really funny exchanges due to their very different personalities.
Well, perhaps in this fanfiction, the SAO system is corrupted by an Orochimaru - like figure. He wants to use the virtual world to gain power and immortality. Naruto and his friends, along with the SAO players, have to team up. Naruto's positive attitude and never - give - up spirit inspire the SAO players. They all work together to defeat this new threat, with Naruto using his Rasengan in new and creative ways within the SAO world.
A plot could involve the Killzone characters getting access to chakra. Some of the Killzone soldiers might start to learn ninjutsu and this causes chaos in their own military structure. Meanwhile, Naruto has to figure out how to get back to his own world while also dealing with the new threats that this crossover has created. Maybe he teams up with some of the more honorable Killzone soldiers to find a solution.
One possible plot could be that Thor somehow gets transported to the Inuyasha universe. Thor's powerful hammer and lightning powers would be a huge asset or a source of conflict. Maybe the demons in the Inuyasha world see Thor as a threat or a powerful ally to be manipulated. Inuyasha and his group might initially be wary of Thor but then realize they can work together to defeat a common enemy, like a powerful demon that is causing chaos across the land.
Another plot could be that an evil force in the RWBY universe discovers the existence of the Omnitrix from another dimension. They manage to create a device to pull Ben and the Omnitrix into their world. Ben has to adapt quickly to this new world while Team RWBY, who are initially suspicious of him, realizes that he could be an ally against this new threat. They join forces, with Ben using his alien forms in creative ways to combat the Grimm and the evil force's minions.