Machine G's name comes from "Machine" and "G," which can come from either Godzilla or the "G" in Mecha G's creators, "Team G."
Machine G is a sleek Mechagodzilla which looks unlike any that preceded or followed it. It has a long, almost canine-like head with a massive black spike erupting out of it, and a gem in its forehead. He also has spikes running down the back of his neck, but lacks the dorsal plates of other MechaGodzillas. He has powerful arms and large shoulders, and the top half of his body appears to be heavier than the lower half. His tail, arms, legs, feet, chest and groin are all protected by thick black armour.
Machine G was deployed by Team G shortly after Godzilla defeated King Ghidorah III and Neo Gigan. Team G felt that Godzilla's power made him too much of a threat to ignore. Godzilla confronted Machine G in a city, and the two fought, with Machine G clearly having the upper hand. Eventually, Godzilla had to retreat to slowly regenerate some of the damage that Machine G had incurred upon him. Machine G left the battle relatively undamaged. Later, after Doctor Oniyama releases King Godzilla, Team G watch Godzilla's struggle against King Godzilla, and decide to deploy Machine G to help Godzilla in the fight. Godzilla blasted a hole through King Godzilla's chest, but King Godzilla grew his Biollante Head and began decimating the Kaiju king before dropping him onto some spikes, forcing Machine G to fight alone. Machine G used his Twin Maser Cannon Hands to deal devastating damage on the cloned kaiju, but King Godzilla regenerated his damage. King Godzilla then slammed into Machine G, throwing him to the ground. King Godzilla then attempted to destroy Machine G by trying to stomp on the mecha's head, but this distraction enabled Godzilla to lunge at King Godzilla and grab them, buying Machine G enough time to escape. Machine G then assists Godzilla and observes as Godzilla throws himself, Oniyama and King Godzilla into the mouth of the active volcano near the battlefield.
- Machine G can deploy wings and fly.
- Machine G's hands can transform into Twin Maser Cannons.
- Machine G has cannons that shoot missiles.
- In the entire manga, Machine G is the only opponent who survived battling Godzilla.
- Machine G's name, build, and flight ability all are a reference to Mazinger Z.