There are also Forerunner characters that show up in some fanfictions. Since the Forerunners were the ones who originally dealt with the Flood, they might appear in flashbacks or as some sort of guiding presence, especially if the story is exploring the ancient history of the Flood in the Halo universe.
Spartans are often main characters. Their enhanced abilities make them prime candidates to face the Flood. They can fight and strategize in ways that ordinary soldiers can't.
Master Chief is one of the main characters. He is a super - soldier and plays a crucial role in the fight against the Flood. His strength and combat skills are vital in many battles.
In 'halo the flood graphic novel', Master Chief is definitely one of the main characters. He's known for his combat prowess and leadership. Other characters from the UNSC might also be main characters as they work together to face the Flood. There could also be Covenant characters who play important roles. Since the Covenant also has to deal with the Flood, their leaders or elite warriors might be shown as main characters in the story. For example, an Elite who has a different view on dealing with the Flood compared to his comrades could be a main character, adding more depth and conflict to the story.
I'm not entirely sure, but it could feature characters like Master Chief. Since he's a central figure in the Halo series, he's likely to be involved in any story related to the Flood.
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.
There are likely various UNSC characters involved as they often fight against the Flood. Captain Cutter is one possible main character who would be in the thick of things when dealing with the Flood threat.
In halo prehistoric human fanfiction, the main characters are usually prehistoric humans themselves. Some could be shamans who have a special connection to the spiritual side of the Halo elements in their world. And there are likely to be brave warriors who protect their tribe from any threats related to the Halo, whether it's other tribes that have been corrupted by Halo technology or strange alien creatures that are attracted to it.
Often in 'halo scarab rwby fanfiction', Ruby and her friends are main characters. Ruby, as the protagonist of RWBY, has the drive to explore and face new challenges, which the Scarab represents. Halo's Arbiter could also be a main character. His unique backstory and combat skills could add an interesting dynamic. Blake, with her stealth and intelligence, would be important too. She could be the one to gather information about the Scarab or any threats associated with it. And Weiss, with her ice - based powers, could be crucial in combat situations against the Scarab or its related foes.
Master Chief could be one. Since he's such a central figure in the Halo universe, it's not hard to imagine him being part of a dragon transformation story. Cortana might also be involved, perhaps as a guiding force or even as a character who undergoes some sort of transformation herself. The Arbiter could be another popular choice. His complex character and role in the Halo story make him a likely candidate for this kind of fanfiction plot.
Master Chief is often a central character. His iconic status in the Halo series makes him a natural choice. Writers might send him back in time to change crucial events. Another popular character is Cortana. Her intelligence and connection to the Halo technology can create interesting time - travel scenarios, like she uses her knowledge to prevent a system malfunction in the past that would have had catastrophic consequences.
I'm not sure who the main characters are without reading the story. But they could be ordinary people living in the area affected by the flood, like a family, a local fisherman, or a community leader.