What are some interesting ideas for a Halo Fallout crossover fanfiction?

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.

One idea could be that the characters from RWBY end up in the Fallout wasteland. Ruby could use her scythe skills to fight off raiders and mutants. Weiss might use her glyphs to protect the group from radiation in certain areas. Another idea is that the Dust from RWBY could be a valuable resource in the Fallout world, leading to various power struggles.

A cool concept would be a hybrid character. Imagine a Spartan who has been genetically altered with some dragon DNA. This character could have the strength and combat skills of a Spartan along with the ability to breathe fire or fly like a dragon. Or perhaps the Covenant could be interested in the dragons in the HTTYD world because they see them as a new form of powerful weaponry to add to their arsenal.

Another concept could be a story where a character from Halo, say Master Chief, gets transported to the Overwatch universe. He has to adapt to the different rules and powers there while trying to find a way back home. Along the way, he could form unexpected alliances with Overwatch heroes and learn about their world, and they could learn from his military discipline and combat experience.

For 'halo anime crossover fanfiction', a cool concept is to mix the Covenant from Halo with the Titans in Attack on Titan. The Covenant's alien races and their zealotry could be an interesting contrast to the humans fighting Titans. Also, think about having Cortana, the AI from Halo, integrated into the world of Ghost in the Shell. Her digital existence could bring new perspectives to the cybernetic world of that anime.

One idea could be to have Spartans from the UNSC interact with Halo's Forerunner technology in unexpected ways. Maybe they find a Forerunner device that gives them new abilities or reveals secrets about the Halo rings.

One idea could be a scenario where the Doom Slayer somehow ends up in the Halo universe. He might team up with the Master Chief to fight a common enemy that combines the demons from Doom and the Covenant or Flood from Halo. For example, a new threat that has the ability to corrupt both the technology in the Halo universe and summon Doom demons.

Perhaps a crossover where Master Chief and Ruby Rose meet. They could exchange their combat experiences. Ruby could be amazed by Master Chief's Spartan enhancements and weaponry, while Master Chief might be intrigued by Ruby's Silver - eyed power. They could then go on a mission together, with Ruby's speed and scythe - wielding skills complementing Master Chief's brute force and strategic thinking.

One idea could be that the rookie gets transported to a different Halo timeline and has to team up with classic Halo characters to face a new, powerful enemy. For example, they might end up in the time of the Covenant War and use their unique skills from their own era to help the UNSC in unexpected ways.

One idea could be that the Spartans from Halo are sent through a Stargate to an unknown planet in the Stargate universe. They have to team up with the SG teams to fight off a common enemy like the Flood that has somehow spread to that planet. Another could be a scenario where the technology from both universes is combined. For example, the Covenant's energy shields are integrated with the Stargate's shield technology.