Kiryu

Kiryu, or Mechagodzilla 3, is a weapon used by the army to stop Godzilla in Godzilla Against Mechagodzilla and Godzilla, Mothra, Kiryu: Tokyo SOS. He is sort of like the Millennium version of Mechagodzilla.

Godzilla Against Mechagodzilla
Even though the original Godzilla was killed by the Oxygen Destroyer in 1954, Japan was still attacked by other monsters. When the new Godzilla arrived, it was the last straw. The Anti-Megalosaurus Force division of the Japan Xenomorph Self Defense Force proposed a shocking plan: they would dig up the bones of the first Godzilla and use it as skeletal framework for a new Mechagodzilla. In short, fight atomic fire with atomic fire (in this case, electricity).

The plan was executed, with cloned DNA from the bones inserted into the quasi-organic computer controls, intending to take over subconscious motor control functions for the crew. In 2003, the robot was ready. It was launched against Godzilla. However, upon hearing Godzilla's roar, the robot remembered how it was once Godzilla. Breaking free of control over his pilot, Akane Yashiro, Kiryu proceeded to go on a rampage while the other Godzilla retreated into the sea. Kiryu comtinued to trash the city until his fuel ran out.

The public was not amused. Kiryu was given several weapon upgrades as well as new computer control software routines. When Godzilla attacked again, the JSDF tried to fight him off without the mechanical Godzilla, but failed. With Akane at the mecha's control, Kiryu was sent out. The battle went well until Kiryu's reciever was damaged. Akane then piloted the robot from the skull. Akane attempted to destroy Godzilla with Kiryu's ultimate weapon, the "Absolute Zero Cannon," but the fight ended in a draw. Godzilla went back to sea with a shredded chest while Kiryu was sent to the body shop after suffering a destroyed arm, a damaged Absolute Zero Cannon, and empty powercells.

Godzilla: Tokyo S.O.S
One year later, Akane went to America for futher flight training. Taking her place is Akiba, but Kiryu engineer Yoshito Chujo is the main focus of the film.

Mothra's twin fairies, the shobijin, arrived at Japan to warn them. They said that building Kiryu from the original Godzilla's bones was a violation of the natural order and that it attracted Godzilla. They say Mothra will gladly take Kiryu's place to protect Japan from Godzilla. Since Kiryu had been built partially to protect Japan from Mothra herself, Japan refused.

But when Godzilla killed Kamoebas, Mothra fought him. Prime Minister Hayato Igarishi was shamed into aiding her. Kiryu arrived and battled alongside Mothra as well. Despite this, Godzilla killed Mothra and damaged Kiryu's transmitter again. Like Akane before, Yoshito entered Kiryu for repairs, but remained inside after Godzilla accidently jammed the doors shut.

Teaming up with the two Mothra larva, they fought and damaged Godzilla's chest even more before tearing up the insides. Kiryu fired his Triple Hyper Maser, making Godzilla roar in agony and triggering another flashback that was cancelled by Yoshito. Unable to fight, Godzilla callapsed, and Kiryu broke free of Akiba's control. Rather than killing Godzilla. Kiryu subdued him and dragged him to sea before plunging in with him, never to be seen again.