Pretty much Spartans.

lol. I know, big surprise, right?

There are so many short stories I can think of involving them. For example, a story quite similar in premise to both "Midnight in the Heart of Midlothian" and the opening to Halo: CE (coming out of cryo to discover the ship besieged).

- Mendez

- Halsey

- MJOLNIR's development

- Any number of moments from the 27 years of war with the Covenant preceding the games

- Transhumanism

- 9-year old SPARTANs forming the "software" in their minds that will govern who they are when they're adults, and the "parental" efforts to help shape that (fostering of adequate levels of compassion and/or other desirable qualities so that humanity is not simply creating obedient, heartless killing machines out of these genetically-endowed geniuses) from Halsey, Mendez, the trainers, the contracted specialists/experts, and the AI team responsible for the incredibly expensive S2 project.

- Civilian perspectives on an invasion

...the list goes on. :]