All others dead.
Covenant.
Yeh Eternal Slayer is right. They were killed by the Covenenant. So the MC got a new suit. Probably have faster shield re-charge (again).
As I was looking through pictures of Halo 3 I noticed that The "Master Chief" looked very different then in halo 2. First, the spartan in the trailer was suspicious looking his armor was a very light tan, Second he had many gashes and holes in his armor , Third instead of having those little 5-Dots on his hand plate, there are 3. I have reasons to believe master chief is not in the halo 3 trailer, OR the MC got new MJONIR Mark IIV armor. Who knows?
😵
Well, if he looks different, basically you get another suit (like in Halo 2)....
And why does it have to be IIV....It could be an IV
If you read the books, 7 years before MC fought on Halo, the third division of the Spartan III's were already fighting the Covies (as a super secret organization) trained by Kurt, a fellow Spartan II.
Fred, Will and Linda (more Spartan II's) came back to Earth with John and Stg. Johnson and continued to fight the Covies on Earth.
Kelly (yet another Spartan II) was traveling space with Dr. Halsey.
i believe Will died in the new book