Developed for the role of defending large bases, the Zero GR was equipped with a large number of powerful beam weapons which could suppress the enemy with overwhelming firepower, and a defensive I-field generator used to neutralize incoming beam attacks. Originally, an auto-pilot program would be equipped to help maneuver the cumbersome Zero GR, while the pilot would only need to operate the weapons. However, during a mock battle, Char Aznable's outstanding piloting skills allow him to manually operate the entire machine, destroying every indicated target, and leaving the Zero GR unscathed. Although the Zero GR was a powerful mobile armor, Char Aznable disapproved of its low maneuverability.
The AMA-00GR Zero GR is a mobile armor developed by the Zeon remnants at Axis. Designed with location defense in mind, the Zero GR is monstrous in size, even more so than other Mobile Armors, armed with enough firepower to rival an entire enemy fleet. Commissioned by Admiral Dozle Zabi during the One Year War, the Zero GR was meant to be issued to Char Aznable, until the death of Garma Zabi served to pull Char away from Dozle's command. In the time since the end of the One Year War, Axis Zeon managed to complete the Mobile Armor aside from the final settings to the controls. The unit was given to Char Aznable upon his arrival at Axis, in spite of his apprehension towards piloting Mobile Armors. Soon after, the Zero GR underwent combat testing under the skilled control of Char.