Optem

The Optem, also known to the Covenant as the Looters, are or were an Ulterior civilization known to the Covenant. They seem to have showed a particular interest in Forerunner artifacts, and visited various Forerunner sites within the Orion Arm circa 20,000 BCE, stripping those relics of useful technology and data. No contact has ever been made with the Optem, so it is not known whether they remain active in the galaxy or whether their race could be considered as one of the Milky Way's many antecedent civilisations.

When it comes to the Optem, it is difficult to separate fact from myth. While the Optem seemed to take care to leave behind as little evidence as possible, enough minor artifacts and even physical remains have been uncovered in looted Forerunner sites and in surrounding space to identify them as a race distinct from others known to the Covenant. The most obvious tell-tale signs of them are Forerunner structures devoid of technological relics that those sites should should otherwise contain. When encountering Forerunner relics stripped of technology, it is common for Covenant relic-hunters to blame the Optem, even if they cannot conclusively proven to have been the ones responsible. Numerous legends surround them, with many Covenant spacers and archaeologists claiming to have come into contact with the Optem in some way, or found evidence of a visit far more recent than their known era of activity. Some have reported sensor pings of "ghost ships" near Forerunner installations, leading to the common theory that the Optem remain active and are secretly continuing their relic-looting activities under the Covenant's noses. No solid evidence for such recent contact has surfaced, however. These reports are remarkably similar to human legends about the so-called Hidebehinds.

Most discovered pieces of Optem technology have been nonfunctional, though what little has been found suggests they did possess highly specialized tools used for scouring Forerunner relics. Indeed, many examples of Optem technology appear to be modeled after Forerunner equivalents.