Since I haven't read the fanfic, it's hard to say for sure. But likely, there would be UNSC soldiers or commanders. Maybe the Master Chief could be one of the main characters as he is a very important figure in the Halo universe and often involved in major events related to the UNSC.
I'm not sure specifically as I haven't read this particular fanfic. But generally, it might involve the UNSC (United Nations Space Command) in the Halo universe using the Halo installations in a strategic way to bring an end to a war. Maybe they find a way to activate or control the Halo rings without causing the total destruction they are known for.
In fanfic, it could be explored through different character perspectives. Some characters might be in favor of it as a last - ditch effort to end the war, while others would be vehemently against it due to the moral implications. Writers might also explore the technical aspects of firing the Halos, like how the UNSC manages to gain control over them and what kind of safeguards they bypass or ignore.
If the Halo UNSC fires the Halos to end the war in fanfic, it's a very complex situation. First of all, the Halos' power is immense. They would cause widespread destruction across the galaxy. But from the UNSC's perspective, they might think that by doing this, they can end the war quickly. However, there are so many unknowns. For example, how would the other races react if they knew the UNSC was about to fire the Halos? And what kind of new power dynamics would emerge after the Halos are fired? It could potentially create a power vacuum or even new conflicts in the long run.
Master Chief is often a main character. Since he's such an iconic figure in the Halo universe, in fanfiction about the UNSC becoming powerful, he usually plays a crucial role in leading the way. He might be the one to first test out new powerful weapons or technologies.
The main characters in Halo Reach War Story are the Spartans. They are highly trained super - soldiers.
In 'halo the story', the main characters include Master Chief, a highly skilled and powerful Spartan - II. Cortana, an AI, is also very important as she assists Master Chief in many ways. There are also various Covenant leaders who play significant roles in the story, like the Prophets.
The main characters are Master Chief and Spartan Locke. Master Chief is the iconic hero of the Halo series, and Locke is the one sent to find him.
The main characters are Master Chief and Cortana. Master Chief is the super - soldier who does most of the fighting, and Cortana is his AI sidekick who provides support and knowledge.
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.
Master Chief is likely to be one of the main characters as he is very important in the Halo universe.