Mechagodzilla (Godzilla vs. Mechagodzilla II)

Mechagodzilla (メカゴジラ, Mekagojira) is the robotic version of Godzilla. The character first appeared in the 1993 film, Godzilla vs. Mechagodzilla.2

Heisei era
In Godzilla vs. Mechagodzilla 2, when G-Force, an anti-Godzilla organization, salvaged Mecha-King Ghidorah from the ocean, the robotic parts from his body were used to construct Mechagodzilla. When Godzilla appears and attacks Kyoto, Mechagodzilla was sent in to stop the monster. The mecha fought well, but was eventually defeated due to a voltage back-surge during their electrocution of Godzilla, the mecha was sent back to base for repairs because of it.

After it was repaired, Mechagodzilla, along with an airship named "Garuda", were sent to battle with Fire Rodan, when he appeared in the city and started attacking, and Mechagodzilla defeated Fire Rodan by blasting him with its Plasma Grenade, and it knocks Fire Rodan unconscious. Godzilla soon enough returns, and Mechagodzilla turns and faces him. Durring their fight, Mechagodzilla combines with Garuda to form Super Mechagodzilla.

Super Mechagodzilla
After Mechagodzilla and Garuda combined, Super Mechagodzilla releases its full arsenal on Godzilla, knocking the monster down, and Super Mechagodzilla proceeds to destroy Godzilla's own reptilian secondary brain, which it does, and thus Godzilla dies.

After regaining consciousness, Fire Rodan flies over towards the now dead Godzilla and Super Mechagodzilla, only to be blasted down onto Godzilla by Super Mechagodzilla's Mega Buster. Fire Rodan then sacrifices himself, releasing the radioactive energy within his body, and it revives Godzilla.

When Godzilla rises, his level of radioactivity is so high that Super Mechagodzilla's armor plate begins to melt. Godzilla, temporarily supercharged with radiation, destroys Super Mechagodzilla with a Spiral Heat Ray attack. However, despite the defeat, Super Mechagodzilla's crew were able to escape uninjured.

Godzilla Island
In the 1997-1998 Godzilla television series, Godzilla Island, Mechagodzilla, along with Moguera, Jet Jaguar, Medical Jet Jaguar, Fire Fighter Jet Jaguar and Proto Moguera, serve as one of G-Guard's mechas.

Godzilla Against Mechagodzilla
In Godzilla Against Mechagodzilla, Mechagodzilla, who is called "Kiryu" throughout the movie, was built from the skeleton of the original Godzilla.

When the current Godzilla appeared and attack, Mechagodzilla was sent in to stop the monster, but its initial weaponry was of little effect. When Godzilla roared into the sky, something went very wrong, as Mechagodzilla suddenly recovered a memory of the original Godzilla deep in its spinal cells, and it stopped moving for a short while. After Godzilla returned to the ocean, Mechagodzilla started moving again. However, it went berserk when that happened, but Mechagodzilla eventually ran out of energy, causing the mecha to shut down. Mechagodzilla was sent back to base after this.

When Godzilla appeared and attacked again, Mechagodzilla was once again sent to stop him. The second battle went well until Mechagodzilla's receiver was damaged, while the mecha itself was knocked down by Godzilla's heat ray when it attempted to finish him with its ultimate weapon, the "Absolute Zero" cannon. Its pilot, Akane Yashiro, managed to take manual control of the mecha, as the mechanical beast was recharged. After getting up, Mechagodzilla attempted to use its Absolute Zero cannon one last time, although this time, it flew quickly towards Godzilla, took an aircraft fighter out of his mouth, shut his mouth with its own hand, and flew into the ocean with him, away from the city, and Mechagodzilla was able to fire its Absolute Zero cannon on Godzilla, but Godzilla mannaged to survive and Mechagodzilla ended up damaged. While Godzilla returns to the ocean, Mechagodzilla was sent back to base for repairs.

Godzilla: Tokyo S.O.S.
In the next movie, Godzilla: Tokyo S.O.S., Mechagodzilla, who is called "Mecha G" throughout the English dub of the movie (it is still called "Kiryu" throughout the original Japanese version of the movie), has been given a new left arm where its hand can shift into a drill, new black weapons that replaces its blue weapons and a "Hyper Maser" cannon that replaces the Absolute Zero cannon.

Mechagodzilla was sent in to help Mothra to fight back against Godzilla. While Mothra was knocked down, Mechagodzilla continued fighting until Godzilla blasted his heat ray onto one of Mechagodzilla's eyes, knocking the mechanical beast down, damaging it. The mechanic, Yoshito Chujo, was sent to repair Mechagodzilla, and manages to do so, at the dire cost of his ability to escape. Mechagodzilla and Godzilla clash with one another until they both fall onto the Diet Building. when both Mechagodzilla and Godzilla got up, Mechagodzilla shifted its left hand into a drill, and it pierced into Godzilla's chest scar, and the mecha proceeded to drill into the chest scar, causing the monster to scream in agony. Mechagodzilla then fired all of its Maser Cannons onto Godzilla, making Godzilla's roar trigger another flashback in Mechagodzilla which was directly channelled to Yoshito. Godzilla was then wrapped up by the twin Mothra larva web. Unable to fight, Godzilla fell to the ground. Mechagodzilla was then about to finish Godzilla with one last Hyper Maser Cannon, until it broke free of Akiba's control. Rather than finishing off Godzilla, Mechagodzilla, instead, carries Godzilla out to sea. After releasing Yoshito to safety, Mechagodzilla plunges itself into the ocean along with Godzilla, and they were never to be seen again.

Trivia

 * Prior to Godzilla vs. Mechagodzilla from 1993, Mechagodzilla was originally known for for being the main antagonist of two Godzilla films, Godzilla vs. Mechagodzilla from 1974 and Terror of Mechagodzilla.
 * The 1993 incarnation of Mechagodzilla is commonly given the label "Mechagodzilla ", both by fans and in some officially licensed media, notably the Atari games. This name comes from the fact that the official international title of its debut film was Godzilla vs. Mechagodzilla , and that the Heisei version of Mechagodzilla was the second distinct incarnation of the character. The Heisei version of Mechagodzilla is never referred to by the name "Mechagodzilla 2" in its debut film, simply because it is the only version of Mechagodzilla to exist in the Heisei continuity. The rebuilt Showa Mechagodzilla is instead officially labelled "Mechagodzilla 2" by Toho.
 * Mechagodzilla was originally going to appear in Godzilla vs. SpaceGodzilla, but was replaced with M.O.G.U.E.R.A. when it was realized that against the combined might of Godzilla and the machine which nearly killed him the previous year would make the battle too one-sided.