Well, a cool idea for a Halo Pokemon crossover fanfiction would be if the Master Chief discovers a Pokeball during one of his missions. When he opens it, out comes a Charmander. The Chief then has to figure out how to use the Charmander's abilities to his advantage in the Halo battles. Or perhaps the Covenant discovers Pokemon and tries to use them against humanity, leading to a whole new kind of warfare where trainers from both sides battle it out with their Pokemon teams.
In a Halo Pokemon crossover fanfiction, there could be a scenario where the Flood infects Pokemon. This would create a new and terrifying threat as infected Pokemon would have the combined abilities of the Flood and their own Pokemon powers. The Halo characters would then need to team up with uninfected Pokemon trainers to find a way to stop the spread. Also, imagine if Pokemon trainers could use Halo weapons and vice versa. A trainer with a shotgun and a Pikachu by their side would be a really interesting combination.
One interesting concept could be the crossover of Halo 5 characters with characters from other science - fiction universes. For example, seeing Master Chief interact with characters from Star Wars. It could lead to epic battles or unexpected alliances. Another concept might be the combination of Halo 5's technology with that of a different game world. This could create unique weapon combinations or new ways of traversing the game environment. Also, crossovers can explore different cultures within the Halo 5 universe and how they would react to an outside influence.
Another concept is the crossover within the Halo universe itself. Different Halo timelines or story arcs being combined. For instance, bringing characters from the original Halo games together with those from the expanded universe novels in a new adventure that fills in gaps in the overall Halo lore.
In this type of fanfiction, the concept of mixing the grittier, more militaristic feel of Halo with RWBY's more fantastical elements is really engaging. We could see UNSC soldiers trying to adapt to the Grimm - filled world of Remnant. And perhaps the characters from RWBY learning about the Forerunners and their technology. It could open up a world of possibilities for epic battles, new friendships, and the exploration of different values and ethics from both universes.
One interesting concept could be the interaction between the Halo and Flood elements. For example, how the characters from Halo deal with the overwhelming threat of the Flood. Maybe there are unique alliances formed within the fanfiction that wouldn't happen in the original Halo lore. Another concept could be the exploration of different Flood forms and how they adapt to the Halo universe's technology and environments.
One interesting concept could be the combination of Halo's advanced alien races like the Covenant with Starcraft's diverse species such as the Zerg. For example, imagining how the Covenant's religious zealotry would interact with the Zerg's hive - mind instincts. Another concept might be the technological exchange. The energy shields from Halo could be incorporated into Starcraft's units, or vice versa, like Starcraft's psionic technology being used in the Halo universe. It could also be fascinating to see characters from both universes meet, like Master Chief and Jim Raynor teaming up to face a common threat.
In Halo Mass Effect crossover fanfiction, a great concept is the sharing of technology. Maybe the UNSC could get their hands on Mass Effect's element zero and use it to enhance their ships' FTL drives. Also, the idea of characters like Master Chief and Commander Shepard teaming up is exciting. They could learn from each other's combat strategies and leadership skills. This could make for some epic battle scenes against common enemies like the Flood and the Reapers.
One interesting concept could be the Spartans from Halo interacting with the Jedi in Star Wars. Imagine a Spartan being trained in the ways of the Force. Another concept might be the Covenant technology being used in the Star Wars universe, like their energy weapons in the hands of the Sith or the Rebels. And also, the Flood from Halo could be a terrifying new threat in the Star Wars galaxy.
One interesting concept could be the combination of the different alien species from both universes. For example, seeing how the Covenant from Halo would interact with the various alien races in Mass Effect like the Turians or the Asari. Another concept might be the technological mash - up, such as how the Spartan armor could be enhanced with Mass Effect tech or vice versa. Also, the idea of the Flood from Halo being a threat in the Mass Effect galaxy and how the different factions would deal with it is quite fascinating.
Some interesting concepts are the different power sources. In Halo, we have things like plasma and fusion power, while Warhammer 40k has the Warp and its associated powers. How would these interact? Maybe a UNSC ship powered by a fusion reactor has to deal with the unpredictable effects of the Warp when it enters a region influenced by it. And then there's the concept of heroism. Spartans are known for their individual heroics, while in Warhammer 40k, heroism often comes with a heavy price and a lot of religious and ideological baggage. Combining these two views of heroism can make for some thought - provoking stories.
One interesting concept could be the combination of the Flood from Halo and the Necromorphs from Dead Space. Imagine how the two different types of parasitic, body - transforming threats would interact. Another concept might be the technology exchange. For example, how would the UNSC weapons and armor function in the Dead Space universe, and vice versa with the Dead Space engineering and weaponry in the Halo universe.