What are some interesting ideas for a Demon Slayer crossover fanfic?

One idea could be a crossover with the Halo universe. The Doom Slayer could team up with Master Chief to fight against a common alien threat that has invaded both their worlds. They could share their combat skills and weaponry knowledge.

One idea could be that the male OC has a unique power related to sound. He can use different frequencies to either paralyze demons or disrupt their attacks. For example, in a battle against a powerful demon in a forest, he uses the natural echo to amplify his power and gain an upper hand.

One idea could be that the Demon Slayers are brought into the world of My Hero Academia. Tanjiro could learn about quirks and try to figure out how to use his skills in this new environment. Maybe some of the demons also gain quirks which makes them even more dangerous.

Some might consider a crossover with the One Piece world. The Straw Hat Pirates and the Demon Slayers could have an adventure together on the Grand Line, facing both pirates and demons. A crossover with the Sword Art Online world is also possible. The Demon Slayers could enter the virtual world and face new kinds of threats there. Additionally, a crossover with the Fate series would bring together different heroic spirits and Demon Slayers in a battle royale - like scenario.

One idea could be a crossover with 'Sword Art Online'. The Goblin Slayer could be transported into the virtual world of SAO where he has to deal with goblin - like mobs in a different gaming environment. He might use his unique skills and no - nonsense attitude to clear floors and quests in the game.

For a Goblin Slayer crossover fanfiction, consider a crossover with 'Harry Potter'. The Goblin Slayer could be transported to the wizarding world. He would be confused by the magic there at first, but then realize that goblins also exist in this world. He could team up with Harry and his friends to stop a goblin - related dark magic plot. This would bring a unique mix of the gritty, down - to - earth fighting style of the Goblin Slayer with the magical world of 'Harry Potter'.

How about a crossover with 'Fairy Tail'? The Goblin Slayer's serious and methodical approach to slaying goblins could contrast with the more flamboyant and magic - using mages of Fairy Tail. They could team up to fight goblins that have been magically enhanced or are causing trouble in the Fairy Tail world.

One idea could be a fanfic where the Goblin Slayer has to team up with a young mage who is new to the world of slaying goblins. They start off not getting along but gradually learn to work together and respect each other's skills.

One idea could be an OC who has a unique breathing style that combines elements from different existing styles. For example, a mix of water and flower breathing, which could create beautiful yet powerful attacks. Another could be an OC who is a demon but has retained some of their humanity and tries to find a way to coexist with the Demon Slayers. Maybe they form an unlikely alliance with a slayer to fight against more evil demons.

One idea could be a story where the main character has the ability to slay phoenixes and is a new, powerful ninja in the Naruto world. They could be on a quest to find a rare phoenix that has the power to grant a wish.