Black Mechagodzilla resembles the original Mechagodzilla from Godzilla vs. Mechagodzilla, except for its color, which may indicate that this Mechagodzilla is more resilient and evil than the original silver Showa Mechagodzilla. Its eye color is white.
Black Mechagodzilla has the same roars as the original Showa Mechagodzilla.
After facing defeat after defeat, the evil Xilien Zaguresu finally unleashed her ultimate weapon, Black Mechagodzilla. Flying down to Godzilla Island in the old machine, she confronted the Earth monsters and challenged G-Guard's own Mechagodzilla to a one-on one fight. During the battle, however, she cheated and soon took out the silver robot, claiming victory. Unfortunately for her, this prompted the other monsters to attack the Black Mechagodzilla, causing it to malfunction. Zaguresu was taken prisoner at the G-Guard Base, but soon after, a mysterious beeping noise within the Black Mechagodzilla prompted the Commander and his alien sidekick Torema to release her to investigate. She escaped, and Torema entered Black Mechagodzilla and discovered that a bomb is the source of the beeping. However, the device proved to be a dud, but the damage had been done. While Torema was distracted by the bomb, but she was not down for long. Right under the noses of the Commander, Lucas and Torema, she stole the G-Guard's Proto-Moguera and used it to finish what the Black Mechagodzilla had started. She ruthlessly attacks the other monsters and the base, and all hope seems lost. However, Torema was able to fix the Black Mechagodzilla, and she used it to fight Proto-Moguera and eventually drive it and its evil pilot back into space.
The powers of the Black Mechagodzilla are much like those of the original Mechagodzilla, but they are approximately ten times stronger.