Jehioi

The Jehioi, Middle Qers'nok for "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. 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 the neighborhood of the California Nebula. 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.