Definitely, Cortana could be a main character in a 'halo anime crossover fanfiction'. If she were in the world of Code Geass, she could help Lelouch with his strategic plans, using her vast knowledge and intelligence. Another option is the Elites from Halo. They could be the main characters in a crossover with My Hero Academia. Their physical strength and warrior culture could be contrasted with the superheroes in that anime, and they could have some interesting interactions with the students at UA High.
Master Chief could be an obvious choice for the human side. He's a well - known and powerful character. For the Covenant, the Arbiter would make a great main character. Their different perspectives and skills could create an interesting dynamic.
Obviously, Harry Potter could be one of the main characters. He could be the one to bridge the gap between the two worlds, using his courage and magic skills. Master Chief from Halo is also a great candidate. His combat experience and leadership would be valuable in the wizarding world full of new threats. Hermione would also be important as her intelligence could help in understanding the Halo technology.
The Spartans from Halo would also be great main characters in this crossover. Their super - human abilities and combat training would make them stand out in the Supreme Commander world. They could be the ones to teach the Supreme Commander forces about hand - to - hand combat and stealth operations, which are not as emphasized in the Supreme Commander gameplay.
For a more unexpected choice, you could have the Arbiter from Halo as one of the main characters. He has a complex backstory and his own code of honor. In a crossover, he could team up with a Hunter Guardian. The Hunter's brute strength combined with the Arbiter's strategic thinking would make for an exciting story as they face challenges in both universes.
The Arbiter is another character. Given his complex relationship with the Covenant and his newfound alliance with the UNSC in the Halo series, his perspective would add depth to a crossover story. He could provide valuable insights to Noble 6 about the Covenant's inner workings and help in diplomatic situations if needed.
Obviously, the fem Harry Potter would be one of the main characters. And perhaps she could meet Naruto in an anime world. Naruto's determination and her own magic skills would make them a great duo to face challenges together.
Master Chief is often a popular character. Given his significance in the Halo universe, it's natural for him to be a central figure in crossovers. He has the skills and determination to face the Flood threat. Another one could be the Arbiter. His unique perspective as a former Covenant and now an ally in the fight against common enemies makes him an interesting addition in fanfictions involving the Flood.
Master Chief is often a very popular character in Halo crossover fanfiction. His iconic status and combat skills make him a natural fit for crossovers. Writers like to put him in different scenarios and see how he reacts.
A Spartan - II could be a main character. Their enhanced combat abilities and strategic thinking would be crucial in the battles that take place in the Halo universe of the fanfiction.
Master Chief from Halo is an obvious choice. His super - soldier skills and stoic nature would be really interesting to see in the Mass Effect universe. Another one could be Commander Shepard from Mass Effect. Putting Shepard in the middle of a Halo - style conflict would be exciting. And Cortana, the AI from Halo, could also play a major role. Her intelligence and relationship with Master Chief could be explored in new ways when combined with the Mass Effect elements.