One idea could be that Lucifer from 'Lucifer' ends up in the 'Supernatural' universe and teams up with the Winchester brothers to fight a common enemy, like a powerful demon that's causing chaos in both their worlds. Maybe he uses his charm and powers in a unique way to help them out.
One idea could be that Lucifer from 'Lucifer' enters the world of 'Supernatural'. Maybe he teams up with the Winchester brothers to fight a common enemy, like a new type of demon that is causing chaos in both their realms. He could use his devilish charm and powers in a way that the Winchesters are both skeptical and intrigued by.
One idea could be to explore a world where the characters from 'Lucifer' and 'Arrow' are forced to team up to stop a common supernatural threat that is beyond the capabilities of either group alone. For example, a powerful demon that is using advanced technology to cause chaos in both their worlds.
One idea could be that Lucifer, with his charm and manipulative skills, gets involved in the power struggles among the Autobots and Decepticons. He might try to use their war for his own amusement or to gain some sort of power. For example, he could offer a deal to Megatron to help him defeat the Autobots in exchange for something valuable in the underworld.
One idea could be a fanfiction where Lucifer and Michael are forced to team up against a new, greater threat. Maybe an ancient evil that even their father couldn't have foreseen. They start off hating each other but as they fight side by side, they begin to understand each other's perspectives a bit more.
One idea could be that they have to team up against a common enemy in the fanfiction world. Since they are mates, their combined powers would be extraordinary. They might start to understand each other's motives better through this shared experience, and it could lead to a deeper bond between them.
One idea could be Naruto crossing over with the world of vampires. Naruto could use his chakra powers to combat the vampires' super strength and speed. Maybe he'd have to team up with some vampire hunters within that supernatural world.
One idea could be that the Winchesters find themselves in the Charmed universe while hunting a cross - dimensional demon. They team up with the Halliwell sisters to defeat it. The contrast between the two groups' hunting styles would make for great drama.
One idea could be that the Winchester brothers are on a hunt in a small town where Hannibal Lecter has set up his practice. They initially suspect him of being a monster, but as they dig deeper, they realize he's a different kind of evil. Another could be that Hannibal gets intrigued by the existence of demons and angels in the Supernatural universe and tries to study them. He might even team up with the Winchesters in an uneasy alliance to take down a greater threat.
One idea could be that the Winchesters end up in Smallville while hunting a demon that has some connection to LuthorCorp's experiments. Maybe the demon is using the kryptonite there for its evil deeds. Another could be that Clark Kent discovers the existence of the supernatural world through Sam and Dean. He could initially be skeptical but then realize there are threats that even his powers might not be enough to handle.
The clash of different mythologies. 'Lucifer' has its own take on the devil and the afterlife, while 'Supernatural' has a vast array of demons, angels, and monsters. When these two universes collide in a fanfic, it creates a really interesting dynamic.