Jega dropped from a phantom, immediately activating his active camo as he landed on the grounds of Zeta Halo. He had orders to kill you specifically, and since he enjoyed killing spartans, he was more than fine with it.

He stalked you from a distance in the trees and the darkness of night, which in combination with his active camo, made him nearly impossible to spot. As he watched your every movement, he realized you had no allies accompanying you, which was perfect. It made this all that much easier.