A new Reddit thread is exploring whether Halo fans expect the Arbiter to make a return in Halo 5 and what role the elite might play in the game.
User Pepperoni-Nipps wrote:
"I believe he will be. Re-reading Halo: Glasslands I've noticed a few similarities it has with Halo 4's plotline. Off the top of my head: the whole idea of Spartans not being machines but real people, and the introduction of Infinity and the Spartan 4s. Considering the possibilty 343 Industries took some of these themes and applied them to the story of Halo 4, you can guess where the story will take you in Halo 5.
"The whole end of the Covenant War was a big plotline cliffhanger which they haven't as of yet acknowledged the huge impact it has had (in the games) so it would make sense that they add a protagonist to take you through the 'great schism' and what happens after, introducing the Arbiter."
He notes that 343 could employ the same strategy Bungie did in Halo 2 and have players spend the majority of the game playing as Chief in a bid to save Cortana but occasionally show the events happening in Covenant space following the war through the Arbiter's eyes.
Many fans expressed the wish to play a level on the Arbiter's home planet of Sanghelios but as the world is inhospitable to humans this would have to be as the Arbiter.
The Arbiter has appeared in recent Halo comics and UNSC is searching for him in some of the novels so there's a strong chance he'll be in the next game as well but whether that's as a playable character like in Halo 2 or an AI controlled ally a la Halo 3 remains to be seen.
You check out some fan theories on Halo 5's story here.