Posted by: Dark Shinobi 93
ok, this'll sound like a loop-hole, but bare with me and let the nerd work...
Those elites (im gonna code-name them "Assassins") are sent out to find and kill headhunters. Assassins will kinda act as a anti-body and try like hell to weed out any Spartans they come across. Now anyone who watched Headhunters and paid attention know that the headhunters' jobs were sabotage, recon, assassination, whatever. Just Suicidal jobs. So through my eyes, they are the covenant equivalent to Headhunters, and so they're own unit.
I'm guessing tho, that the mission to kill the two headhunters "Failed" (considering # of elite deaths to human) they abolished the said unit of Assassins and that would explain why we didn't see anything like it since that