The Big O Wiki
Bigs - Megadeus

The 3 "Bigs"


In the tradition of Japanese monster movies, "The Big O" features monsters modeled after conventional or mythological creatures. There is much confusion over what defines a "megadeus". The term is officially used to refer to all robots seen in the series, but is usually used by fans to exclusively refer to the "bigs".

Instead of blocky body parts, Sato designed a mecha where the chest and hips were not separate from the rest of the body. Big O is slow, lumbering, and heavy compared to more agile and lighter mecha featured in other anime series. That way, movement would seem sluggish, comparable to the giants of old tokusatsu shows. According to Sato, the name "Big O" comes from the opening theme of "Daitetsujin 17", "Oh! Giant Ironman".

The megadeuses are portrayed as semi-sentient beings, capable of acting on their own. Unlike the mechas of other robot anime, the megadeuses do not exhibit ninja ability; what they lack in agility, they offset with sheer power. The Megadeus's are heavily armed with weaponry like missiles, blade weapons, machine guns, and lasers.

Unlike other mecha series, where the robot's weapons come from specifically designed equipment or spiritual energy, the creators of "The Big O" used older technologies as the starting point.

The use of "Cast in the name of God, Ye not guilty" is a design of series director Kazuyoshi Katayama. Katayama first learned of the phrase through a magazine article on John Milius and the "Conan the Barbarian" series. According to the article, the phrase comes from the swords of executioners in the 17th century. A variation of the phrase ("Suffer no guilt ye who wields this in the name of Crom") is engraved in Conan's sword. Katayama liked the sound of it and decided to use it as the call to arms.

The nature of the megadeuses is tied to the event 40 years prior. Several of Roger's dreams suggest that Big O and several other Big-type megadeuses played a part in the cataclysm that destroyed the world. His dreams and nightmares show the Big models attacking the city and marching in formation into battle, while a winged giant oversees the onslaught. Other flashbacks show Roger in a military uniform while piloting Big O. ("Hydra")


Megadeus is the name given to the robots in the series “The Big O”. Not much is known about how they are created, why they are created, or even what their original purpose is. The name “Megadeus” is primarily used when referencing the three main megadai a.k.a. "bigs" (Big O, Big Duo, Big Fau). Those who are able to successfully pilot the megadai are typically considered to be a “dominus”. The word "Megadeus" is a combination of the word "Mega" (greek for "Great") and Deus (Latin for "God") and given the nature of the series the Deus is most likely a reference to Deus Ex Machina (Latin for God from the Machine) the phrase comes to English usage from Horace's Ars Poetica, where he instructs poets that they must never resort to a god from the machine to solve their plots. He refers to the conventions of Greek tragedy, where a crane (mekhane) was used to lower actors playing gods onto the stage. The machine referred to in the phrase could be either the crane employed in the task, a calque from the Greek "god from the machine" ("ἀπὸ μηχανῆς θεός," apò mēkhanḗs theós), or the riser that brought a god up from a trap door. The idea is that the device of said god is entirely artificial or conceived by man.

Jewish Mythology Allegory[]

It is popularly believed that the three "bigs" (Big O, Big Duo, and Big Fau) all are allegories of Jewish Mythological Creatures: Behemoth, Ziz, and Leviathan respectivley. Behemoth was a giant land creature, Leviathan was a creature of the seas, and Ziz was a creature of the skies. These creatures are characterized as the "bigs" when seeing the "bigs" abilities. Big O, specializing in land attacks. Big Fau specializing in easy movement in the sea, and Big Duo being able to fly. In several instances Vera Ronstadt refers to Roger (and Big O) as "Behemoth". During Act: 17 Schwartzwald refers to an entity known as Leviathan, it is believed that the Megadeus that attacked the city was Leviathan. However, in actuallity it refered to Alex Rosewater himself. While there is no reference to Schwartzwald, himself, as Ziz it is estimated.


  • "Cast in the name of God, ye not guilty": the pilot is accepted.
  • "Cast in the name of God, ye not": the Megadeus refuses to activate. ("The Third Big")
  • "Cast in the name of God, ye guilty": the pilot is killed. ("The Big Fight")


  • Action: informs the Big that combat is near
  • Showtime: informs the Big that combat has begun


A Dominus is the pilot of a Megadeus. According to Schwarzwald, pilots who control Megadeus' are chosen by the mechas, suggesting a type of sentience. Pilots attempting to control a Megadeus by force are refused or killed.

In "R.D.", Red Destiny states that the fate of a Megadeus pilot is "Destiny". Red Destiny states that the Megadeus's are the "sacred chariots of mankind".

The 3 Bigs are shown to have a tendency to fuse with the dominus, but only succeeds to do so if the latter accepts the fusion. The process of fusion is seen to have multiple cables in cockpit normally connected to its plugs to be plugged into the dominus instead. The dominus is not required to move as cables are controlled by the Big. It causes pain to humans since their body structure is not intended for being plugged into by mechanics. Also, by the dominus's will more cables can be plugged onto his body as shown by Alan Gabriel. Alan claims his senses are completed by fusing with Big Duo, which is not proven on humans. Fusion does not let a Big be controlled without accessing the controls, a dominus must still operate it manually. It appears fusion is irreversible as hinted by Roger and Alan was unable to reverse the fusion.

Roger states fusion is equivalent to "making the Big and dominus into one", while Alex suggests fusion will cause the dominus to be absorbed into the Big's system. Alan's death leaves only his hat ejected from the cockpit and his body absorbed, but it is unknown if it is the result of fusion as Big Duo decided to kill him.

Known Dominus[]

Big Megadeus[]

Other Megadeus[]

Organic Megadeus[]

Manga Megadeus[]


External Links[]