Eagle-eyed Halo fans noticed that Master Chief is sporting a subtle new look in Microsoft's Halo 4 trailer.
According to new developer 343 Industries, the changes aren't just aesthetic. Chief will demonstrate some new behaviour as well, but not without reason.
"There's some story behind his new look," explained studio boss Frank O'Connor in an E3 interview. "There are specific reasons why he looks the way he does and why some of his behaviours have changed. We'll see in good time."
According to O'Conner, some details on Halo's 4 plot - maybe even hints on Master Chief's new mental breakdown - will be sprinkled throughout Halo Combat Evolved: Anniversary.
Have a look at our Halo 4: Dissected feature for some of our thoughts on the trailer.