UPDATE: The below was written in early 2007. Approximately two months before release, Bungie announced that Halo 3 will feature cooperative play via split screen (two players per box) as well as system link and Xbox Live (four players per game). In a four-player game, the host players the Master Chief, and the other players are the Arbiter and two other Elite warriors.

UPDATE: Just before the release of the Brute video documentary, a rumor circulated that the Brutes would be a playable race in Halo 3. Bungie has since denied this. Brutes will not be playable in Halo 3.

Again, nothing specific about the campaign's plot or features has yet been announced.

For my own part, I think it's possible that the Arbiter will be back as a playable character; but I do not see Bungie including other Covenant races such as Grunts, Jackals, Brutes, Drones, or Prophets as playable characters.