One idea could be that the Servants from Fate are transported to the Halo universe. For example, Saber could find herself in a battle against the Covenant. Her noble phantasm could be a powerful weapon against the alien foes. Another plot could involve Master - Spartan team - pairings. A Spartan could be paired with a mage to fight a common enemy that threatens both the Halo and Fate worlds.
Well, a cool plot might be that the Forerunners in the Halo universe somehow get mixed up with the Holy Grail War in Fate. The Forerunners' technology could be mistaken for powerful magical artifacts in the Grail War. And maybe some Spartans get caught in the middle, trying to figure out this strange new world of magic and Servants. Also, the idea of a Halo - themed Servant, like a Servant based on Master Chief, could add an interesting twist to the story.
One idea could be a Spartan from Halo ending up on Pandora. Maybe they team up with the Na'vi to fight off a common enemy, like a new type of alien that's more powerful and dangerous than the Covenant or the RDA. The Spartan could introduce advanced human technology to the Na'vi, which would change their way of life in some aspects. For example, they could use some of the shielding technology to protect their homes. Another plot could involve the transfer of consciousness, like in Avatar, but with a Halo - related twist. Perhaps a character's mind is transferred into an enhanced alien body, similar to the Elites in Halo.
One idea could be that the Master Chief is somehow transported to Skyrim. He might use his advanced combat skills and technology to deal with the dragons. For example, his energy shields could protect him from dragon fire. Another plot could involve the races in Skyrim getting access to Halo's weaponry and having to figure out how to use it. Maybe the Dwemer could reverse - engineer Covenant weapons.
Maybe in the fanfiction, Cortana could be integrated into Iron Man's suit. Her advanced AI could enhance the suit's capabilities even further. And they could work together to take on a new villain that is causing chaos in both the Halo and Marvel worlds. It would be a great mix of science - fiction elements from both universes.
One idea could be that Naruto characters are teleported into the Halo universe. They might use their ninja skills to fight the Covenant. For example, Naruto could use his shadow clone jutsu to confuse the enemy, while Sasuke could use his Sharingan to predict their moves. Another plot could involve Master Chief getting some of Naruto's chakra abilities, making him even more powerful in combat against the Flood.
Another plot could involve Noble 6 having their consciousness transferred into a Forerunner construct in a crossover. This would force them to navigate Forerunner technology and politics while still trying to uphold their UNSC values. They could form an unlikely alliance with a Forerunner AI to stop a rogue element within the Forerunner society.
In 'halo 4 crossover fanfiction', a great crossover idea is with the Ghost in the Shell universe. The high - tech world of Ghost in the Shell combined with Halo's advanced military tech would be fascinating. You could also consider a crossover with the Metroid series, where the Spartans face off against the space - faring threats like Samus does. And a crossover with the Devil May Cry series would bring some stylish combat to the Halo universe.
Well, perhaps the Flood from Halo somehow gets mixed up with the zombie virus in the Walking Dead universe. The characters from both worlds would then have to figure out how to stop this new super - virus. They could form alliances between Spartans and some of the more capable survivors from the Walking Dead. For example, Daryl could team up with a Spartan to take on hordes of Flood - zombies. It would be a really chaotic and action - packed scenario.
One idea could be that the Hogwarts students discover Halo technology. Maybe Harry and his friends find a crashed UNSC ship and start to study its advanced weaponry and shields. They could try to adapt the technology to defend Hogwarts from Voldemort. Another plot could involve Master Chief being sent to the wizarding world by accident. He then has to navigate the strange new world of magic while also dealing with threats that his usual Halo combat skills might not be fully equipped for.
One idea could be that the Winx Club fairies visit the Halo universe to help fight the Covenant. They could use their magic to enhance the Spartans' abilities. For example, Bloom could use her dragon fire to super - heat the Spartans' weapons. Another plot could involve the Halo characters getting lost in the Magic Dimension and having to team up with the Winx to find their way back while also facing threats from the Trix.
One idea could be that the Covenant from Halo discovers Earth while the Justice League is busy dealing with a local threat. The League has to quickly adapt to this new alien threat that has far more advanced technology than most of their foes. They might have to team up with Master Chief, who is also on a mission to stop the Covenant's invasion plans.