The original Onyx Guard (appearing in the "Gears of War: Judgement" video game) was wiped out to the last man by the 17th year after Emergence Day. They notably acted as security for the courtroom when Lieutenant Baird's Kilo Squad was put to trial less than a year after E Day. Most inside where killed after Locust breached the building.
Around 17 AE (After Emergence Day) Onyx Guard members where the main force involved in VIP protection on Azura (a hidden island used to protect the social elite after the split of the COG, Cotillion of Ordered Governments). The Locust where, again, too many to hold back. After the Locust and Lambent (Infected Locust) where all but wiped out, the remnants of the Onyx Guard came back together. They now serve as Military Police units for the, slowly reforming, COG. Permalink