Mechagodzilla (Godzilla vs. Mechagodzilla II)

Mechagodzilla (メカゴジラ, Mekagojira) is the human-made robotic version of Godzilla that made its first debut in Heisei film Godzilla vs. Mechagodzilla 2. While the character were based on the villainous robotic Godzilla of the same name that was built by Black Hole Planet 3 Aliens, there are 2 incarnation of this Mechagodzilla. One is Heisei Mechagodzilla while the other is Kiryu.

Godzilla vs Mechagodzilla 2
Heisei MechaGodzilla is created based on cybernetic remains of Mecha-King Ghidorah that previously defeated Godzilla. It was immediately deployed once Gordilla returns and attacks Kyoto. The mecha fought well, but was eventually defeated due to a voltage back-surge when electrocuting Godzilla with shock anchor cables, where Godzilla wind up redirect the electricity back to MechaGodzilla. As result, the mecha was sent back to base for repairs because of it. After it was repaired, MechaGodzilla, along with an airship named Garuda, later deployed to battle with Fire Rodan, when he appeared in the city and started attacking due to Godzilla Jr. telepathic distress, and MechaGodzilla defeated Fire Rodan by blasting him with its Plasma Grenade, and knocks Fire Rodan unconscious. Godzilla then join the battle, where they battle once more. MechaGodzilla then turned the table over Godzilla by combined with Garuda and become Super Mechagodzilla.

Now with more better arsenal against Godzilla, it fires all of its' arsenal to knocked the monster down. As during its maintenance Godzilla revealed to possesses secondary brain, the pilots of MechaGodzilla immediately uses shock anchor cables to fry Godzilla's secondary brain, paralyze him. At this point, Rodan recovers and interfered, prompting MechaGodzilla to shoot him down with its mega buster. Rodan fell onto Godzilla, and it appeared the two monsters would die together. However, Rodan began transferring his life force into Godzilla, regenerating his secondary brain and revitalizing him.

As Rodan died, Godzilla rose to his feet and roared, giving off huge amounts of heat. The intensity of the heat caused MechaGodzilla's synthetic diamond armor plate to melt. Godzilla fired his new spiral red atomic breath at Super MechaGodzilla, staggering it back and causing severe damage. MechaGodzilla fired back with its mega buster, engaging in another beam lock. This time, Godzilla's beam overpowered MechaGodzilla's, causing it to fall backward into a building. Godzilla proceeded to fire his spiral beam at MechaGodzilla until the mech's head was blasted off and its entire body erupted in flames. Godzilla roared victoriously and went to find Baby Godzilla.

All of MechaGodzilla's pilots survived, but it's computer systems so much that it can't read its pilots' life signature. MechaGodzilla's pilots looked on from afar as Godzilla and his newly-adopted son waded out to sea together, remarking that life always triumphs over artificial life.

Godzilla vs. Spacegodzilla
Though Mechagodzilla is destroyed, its remains later recycled for M.O.G.U.E.R.A.'s construction.

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. It also used to fight its villainous counterpart deployed by Zaguresu. Though both Mechas fought equally, Zaguresu then cheated in the fight that resulting MechaGodzilla's defeat.

Kiryu
Kiryu is the name given to MechaGodzilla that built from the skeleton of the first Godzilla that previously killed with Oxygen Destroyer.

Godzilla Against Mechagodzilla
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.

In spite of Kiryu's success, Kiryu's creation proved to be controversial for Shobijins' Mothra's assistants, whom claimed that building Kiryu using the bones of the Godzilla that appeared in 1954 was a violation of the natural order of things, attracting the current Godzilla. In some was, this proved to be true as the effort in creating Kiryu also involved in desecrating the first Godzilla's remains in process. The twins further claimed that Mothra would gladly take Kiryu's place in protecting Japan if they agreed to dismantle Kiryu, and if they declined, Mothra would attack Japan. Since Kiryu had been built partially to defend against a second attack from Mothra herself, the Japanese declined.

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 2, Mechagodzilla was originally known for for being the main antagonist of two Godzilla films, Godzilla vs. Mechagodzilla and Terror of Mechagodzilla.
 * The 1993 incarnation of Mechagodzilla is commonly given the label "Mechagodzilla II", 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 II, 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.