Question 343 or Fans What Happened to the Arbitor is he going to be in Halo 4 I seen nothing about his role yet!
Role in Halo 4: Unknown.
Role in the expanded universe: He’s busy trying to lead his people back on their homeworld of Sanghelios in the face of a civil war AND potential threats from the Prophet-Brute Covenant Loyalists.
from what we can tell from Glasslands the servants of the abiding truth who are led by Telecam are trying to assassinate the arbiter because he wants to reach a peace agreement with the humans, whats stupid though is that Paragosky is supplying weapons to the servants of the abiding truth to keep the elites fighting among eachother. Haven’t finished the book yet but its pretty sweet 
> Question 343 or Fans What Happened to the Arbitor is he going to be in Halo 4 I seen nothing about his role yet!
If you want to find out what has happened to The Arbiter you should read Glasslands. It’s a good book that really sets the stage for what occurs in Halo 4. I believe Karen Traviss is writing a novel to follow Glasslands that will release prior to Halo 4. That novel will be worth reading as well.