Jehioi

The Jehioi or Jehi'oi ("Wayfarers") were a post-Halo Array civilization who established planetary and orbital colonies in the Orion Arm circa 40,000 BCE. For unknown reasons, these colonies would be abandoned and fall to ruin within less than two millennia, making the species one of many antecedent races which have inhabited the galaxy. Few examples of intact Jehioi higher technology such as computers have been discovered, with the ravages of time having rendered most such technology nonfunctional. Based on their remains, it is most likely that the Jehioi were a Tier 2 culture with a mature fusion economy and long-distance slipspace travel.

Jehioi architecture is peculiar in its heavy emphasis on verticality and scarcity of conventional streets, hinting that their builders were likely arboreal in origin. Surviving Jehioi statues and carvings support this, depicting tall creatures with long limbs and digits. Due to this, some Covenant scholars have suggested they might be related to or even the same species as the Ior, a largely arboreal Covenant fringe species inhabiting a world in what is now the Holy Ecumene's Ulannon Migration, with the Ior supposedly being a primitive offshoot population left behind from the species' expansions. It is not known whether Jehioi remain active elsewhere in the galaxy, though one abandoned colony displaying their characteristic architecture has been found as far as the Perseus Arm.

The civilization's name is derived from a from a Middle Qerenoka term that can be translated as "Wayfarers" or "Explorers". In the modern standard register, most speakers pronounce the name as "Jehi'ai" due to changes in the final /oi/ diphthong.