Doku and Kuro serve as Rock-chan's babysitters while De-chan is working at the shop. They display rudimentary intelligence and personalities.
Black★Rock Shooter OVA
Unnamed. Here they appear much larger and seem to act purely as weapons for Dead Master. They are destroyed by Black★Rock Shooter's sword.
Black★Rock Shooter (2012)
Here portrayed as two enormous skulls that are created by Dead Master to combat Black★Rock Shooter. They create a giant body together from the ground and undead army parts to kill Black★Rock Shooter but are destroyed when she explodes them with her Rock★Cannon