Floating, serene aliens known as Engineers, or "Huragok", were pulled from "Combat Evolved" but made later appearances in the "Halo" novels. They also appeared in "Halo Wars", ', and '. Though Engineers possess no actual combat abilities, they can sometimes aid players or enemies. They are actually artificial lifeforms created by the long vanished and technologically superior race known as the Forerunners. The sole purpose of Engineers is to maintain, repair, and upgrade technology. Although they were originally created to maintain ancient Forerunner technology, they were eventually enslaved by the Covenant to build and maintain their technology. Engineers "reproduce" by assembling progeny out of stock materials and sharing their collective knowledge with the offspring.