Gigan

Gigan is a cybernetic monster that was created by aliens and an antagonist monster from the Godzilla movies. In the Showa series, he was very strong and was a difficult and brutal opponent as he can make the heroic Godzilla bleed rapidly, while in Godzilla: Final Wars, Godzilla defeated him in less than a minute without any allies, but returns later in the film and is killed by Mothra. Although not as famous as King Ghidorah, Godzilla, or Mothra in the United States, he still remains popular to American fans who know him. Gigan has appeared in three Godzilla films twice in the 1970's and returned in 2004. He served as the main antagonist of Godzilla vs Gigan, the secondary antagonist in Godzilla vs Megalon (with Megalon as the main villain) and the tertiary antagonist of Godzilla Final Wars (with Controller X being the main antagonist and Keizer Ghidorah being the secondary antagonist). He is arguably the tertiary antagonist of the Godzilla series.

Godzilla vs. Gigan
Gigan, along with King Ghidorah, was summoned to Earth by the Nebula M Spacehunters (or Nebulans as they are also called), so as to aid in the conquest of Earth, starting with Tokyo. The pair were challenged by Godzilla and Anguirus and were defeated after a long and hard battle.

Godzilla vs. Megalon
The Nebulans later sent Gigan to help Megalon, a monster controlled by a race known as the Seatopians, in his fight against Godzilla and Jet Jaguar. But yet again, Gigan met defeat and left his ally to flee back into space.

Zone Fighter
In a crossover between the TV series, Zone Fighter, and the Godzilla movies, Gigan was commanded to help the Garoga, another group of aliens, fight Godzilla and Zone Fighter. But, after receiving a severe pummeling from the King of the Monsters, Gigan fought and met his end at the hands of Zone Fighter.

Godzilla Island
Gigan appears in the 1997-1998 television series, Godzilla Island as the honorable main antagonist of Story 5. He also briefly appeared in the Story 12 episodes "Gigan Appears" and "Until That Day" as a hero where he helps Godzilla fight Destoroyah and Megalon. Gigan made one more appearance in Story 16 as an anti-hero.

Godzilla Final Wars
In the Millenium era, Gigan was a cyborg that had been defeated over 10,000 years ago by the guardian kaiju, Mothra. The organic/cybernetic monster was revived by the Xilians' commander who activated him since Xillians can control kaiju such as Gigan that have the 5th blood type - M Base. Gigan then destroyed the Earth Defense Force Headquarters building with his eye-lasers and wreaked havoc on Tokyo killing several people in his destruction. The Gotengo crew, the last resistance for humanity's future, rushed to Antarctica to free Godzilla so he can fight all monsters controlled by the Xillians.

Gigan was sent to the South Pole so as to destroy the ship, Gotengo, only to find himself confronting the newly reawakened Godzilla. In the ensuing fight, Gigan's head was blasted off, but the Xilians repaired him so as to aid their other monster, Monster X. Gigan battled Godzilla alongside Monster X until his old enemy Mothra showed up. In the fight, the cybernetic monster set the guardian kaiju ablaze with his eyebeam and seemed to kill her. However two of his razor discs, which he had fired during the battle, came back and cut his head off. Mothra then finished him by slamming her fiery body onto him, generating an enormous explosion.

Abilities
Gigan has high destructive capabilites, being a giant monster, and possess a pair of hooked claws/blades and a saw on his chests, which makes him even more deadly. Gigan can also fly at Mach 3 and fire energy beams from its visor and after being upgraded.

Godzilla: Unleashed
Gigan appears in the game Godzilla:Unleashed as a playable monster. Although,the Showa version is exclusive to the PS2 version of the game and The Millennium version is exclusive to the Wii.

His bio states:

Height: 95 meters

Weight: 47,000 tons

"Gigan is the vanguard of the Alien Invaders. He is the finest fighting monster the Vortaak have at their command. Gigan is a cyborg infused with Vortaak technology designed to augment his powerful natural combat abilities. This latest upgrade makes him faster, stronger, and more ferocious than ever. Gigan projects powerful alien energy from his single eye to engage opponents at range, though with quick footwork and lightning-fast edged attacks he is clearly designed with close combat in mind."