- "Any and all reinforcements to the East Wing! Black-Four is getting hammered over here!"
- —An Onyx Guard soldier requesting backup for Black-Four
Black-Four was an Onyx Guard infantry squad that fought during the Destruction of Halvo Bay. They were stationed at the Museum of Military Glory before being completely wiped out by General Karn and his soldiers.
Destruction of Halvo Bay
- "You! Hold this room. There's something big out there!"
- — A member of Black-Four ordering Kilo Squad to defend the East Wing.
The three surviving members of the squad were eventually relieved by Kilo Squad, allowing them to join the fight outside the museum. They were presumably wiped out when General Karn assaulted the museum. 
- Gears of War: Judgment