Okay, basics down first.

Zeta Halo and the Ark will be the main rallying area for the UNSC and everyone else later. The main base for the group will be the UNSC Infinity, which will be stuck on the Ark. The Swords of Sanghelios will have some of its members on the ship alongside a newly recreated iteration of the Silent Shadow.

Additionally, the UNSC Infinity can produce both Covenant, Banished and some Forerunner tech.

Since the story takes place sometime after Halo Infinite, Chief will have all the equipment he acquired during that time and his Gen3 Mjolnir armour alongside the Weapon who now goes by Celestia. I'm thinking of calling her Cortana, but that just doesn't feel right somehow.

Other Spartans and Halo aliens will appear in the story, and I've already plotted out how the story will end, but how we get to that ending is still up in the air at the moment.

The Banished will become the third biggest problem during the Reaper invasion, second only to Cerberus. Additionally, more of the Endless will appear in the story as well.