Quote Originally Posted by CoDeX View Post
Elites hated Brutes. Since Elites controlled the military. Brutes didn't see much action. Drones were mechanics. Because the covenant were losing soldiers, although not as much as humanity, they were forced to use drones in combat. Skirmishers and Jackals are the same species. Skrimishers were probably few in number so they may have been wiped out during the Battle of Reach.
This is a reasonable thought out answer, thank you CoDeX and I have already filled in more blanks on my own but sometimes to get people thinking someone has to ask the questions