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Official artwork for the Gigadeus, by Keichii Sato

"A love-tap? If Your's is a Megadeus, then mine must be a Gigadeus!"--Beck


The Gigadeus was a large megadeus that appeared in the manga. It was piloted by Beck, who recieved it from Angel. After initially dominating the fight against Big O, Beck eventually started spiraling out of control into insanity caused by the Gigadeuses influx of memories and hallucinations, distracting him long enough for Roger to use his Chrome Buster to destroy it, seemingly killing Beck in the process.


The Gigadeus was a 3-headed tripedal giant robot roughly twice the size of Big O. It's coloration is unknown due to being a manga exclusive. It has a streamlined yet bulky aesthetic similar to that of the big-type megadeuses, such as the heftier shins, the gigantic forearms, the spiky hip section, numerous bolts and hole patterns, as well as some of it's own unique details, like the ornate chest area. It also bears some features resembling the archetypes, like the big empty holes in the heads with pin-prick lights at the center. It's 3 heads are shrouded inside of the 3 large horn-like structures atop it's shoulders, resembling a crest. Each head inside is the size of Big O's head roughly, and they can emerge from the horns like serpents, with tentacle-like "necks". Each head has it's own distinct design, the right head having no eyes, the central head having no mouth, and the left head resembling a dragon.  It has 2 massive drills at the back of it's forearms, and 2 giant sawblades under it's "crest" and above the shoulders.


Judging from at least 2 of Gigadeuses 3 heads, Gigadeus seems to be based off pictoral maxim known as "The 3 Wise Monkeys" and the phrase "see no evil, hear no evil, speak no evil", and it's western interpretation to representing immorality, irresponsibility, and ignorance, which perfectly coincides with Beck's behavior, the increasingly morbid wisdom of Gigadeus and it's memories, and the western style of Big O as a series.

Giga is Greek for giant, so the direct translation of Gigadeus is "Giant God". Multiple hints are given that the Gigadeus is an allegory for the Biblical Garden of Eden, specifically regarding the Tree Of Knowledge. Evidence includes it's nature as a source of cursed knowledge, it's 3 snake-like heads, and the recurring visual hallucination of a giant tree associated with it, being seen twice overall, once in Volume 5 and the other in Volume 1 of Lost Memories, the only memory attributed to it that appears more than once (possibly 3 times if the tree shown by Dantalion in Chapter 13 is included)

Abilities and Traits[]

Gigadeus was heavily armed with the previously-mentioned drills and sawblades, and also featured weaponry on it's heads. The central head has a set of lasers that can shoot out, and were powerful enough to overwhelm Big O's standard eye lasers. Then his left head possesses fire breath. It's unknown if the head at the right has any special abilities.

The Gigadeuses armor was impressively durable, easily withstanding, Sudden Impact, Arc Line, and Missile Party from Big O. It also possessed lots of brute strength, being able to kick Big O into the wall with it's central leg, and also accidentally destroying it's left hand when it missed a punch on Big O, ramming it into a wall and completely destroying it. The only weapon Big O used on it that was effective was the Chrome Buster, which blasted Gigadeuses upper half into pieces.

The most peculiar feature of the Gigadeus was it's ability to show memories from 40 years ago en masse. Unlike in the anime, where memories prior to 40 years ago usually consist of the megadeus onslaught during The Event,  Gigadeus exhibit's memories of world history. The evolution of flight technology, the history of warfare, and even space programs. There doesn't seem to be any limit to what memories the Gigadeus possesses, and they seem to only come out as per Gigadeuses' own accord. It's unknown if these memories are able to appear when above ground, as, according to Beck, Gigadeus allows him to "see" the memories underground.

Unfortunately, there's 2 negative side-effects to being the Gigadeuses' pilot: First, the overwhelming amount of memories become addictive according to Beck, and it's easily seen as his personality shifts dramatically, from apathetic and empty when on the surface (instead of his regular cooky demeanor) to completely manic and insane when piloting the Gigadeus. Secondly, and perhaps tied with the insanity, morbid and disturbing hallucinations seem to follow after the waves of memories, depicting death, corpses, and disturbing imagery, though this is mostly seen at the end.

Only 2 people are confirmed to have experienced these memories from Gigadeus: Beck (who got repeated exposure until the point of insanity) and Roger (during his fight with Beck and the Gigadeus).


Gigadeus was introduced in Chapter 16 of the manga, "In Darkness", and is piloted by Beck and used to fight, overwhelm, and nearly defeat Roger and Big O. Throughout the beginning of the Manga, Beck shows signs of a mental decline of some kind, being far more frivolous than usual and showing signs of apathy and lethargy. It's revealed that these are likely the effects of Gigadeus' corruption, as during this time he was led to the heavy metal unit by Angel, who knew in full detail what corrupting power it had. Beck uses the Gigadeus to overpower Roger and Big O and bombard them with memories of the world prior to 40 years ago. However, Beck's mental decline was too great for him to finish the job, and during one of his unhinged monologues Gigadeus was destroyed by Big O's Chromebuster, seemingly killing Beck in the process.

However, it's revealed Beck may have underwent some kind of ascension in the end of Volume 6, as he reappears to haunt Angel and get payback for her leading him on into that cursed machine, and forces Angel's wings to emerge and pulls her out of Big Fau, presumably to activate Big Venus. This is further proven in the release of the first volume of Lost Memories, where Beck spends the first 5 chapters haunting Roger and gradually destroying his sanity with various tricks and schemes while posing as a client, before then completely cursing him and trapping him in an endless torrent of morbid hallucinations that soon leave him catatonic and unresponsive for a whole chapter. This is seemingly tied to the power of the Gigadeus, which reappears in the numerous morbid hallucinations and seems to have been the cause for Beck's new supernatural powers. In the end however, the curse eventually breaks off, seemingly because of Dorothy, and Beck wouldn't appear again until Volume 6.


  • Gigadeus is the second largest robot to ever appear in the Big O franchise, with only Behemoth being larger by a massive margin.
  • Gigadeus is one of the few robots in Big O to pose a major threat to Roger and Big O and even be capable of overwhelming them. Some of the few robots capable of this are the other Bigs, Big Duo and Big Fau. Combined with their vaguely-similar aesthetic and unique ability to summon memories from prior to 40 years ago, and it's possible Gigadeus is in the same league of core memory and technological advancement as the Bigs, possibly even greater, or serving as one of the original archetypes, next to the Archetype and Leviathan.
  • It's possible Gigadeus has a connection to 2 other megadeuses in this series: Osrial from Episode 5 of the anime and Dantalion from Chapter 13 of the manga: Osrial has a similar 3-headed design and illusionary powers whilst Dantalion is able to summon memoires from 40 years ago, the latter even summoning a memory similar to the recurring vision of a tree Gigadeus is associated with, further implying a connection.
  • Gigadeus has the most Paradigm Gallery notes attributed to it with a total of 3, with Big O itself only having more in the form of it's different configurations exclusive to the manga. Firstly, Paradigm Gallery reveals some design notes for the Gigadeus: It was commissioned by Hitoshi Ariga to Keichii Sato, intended to be a strong, serious design resembling a Big, but with a slightly non-humanoid design, being double the size of Big O, and specifically armed with drills.
  • Secondly, it's 3 heads symbolize the past, present, and future, with the head lacking eyes seemingly in control of the memories and no known other abilities. The mouthless head uses the same eye lasers as the Bigs, but more powerful, and extra emphasis was put on the power of the dragon head's flame attack.
  • Lastly, Paradigm Gallery reveals some interesting new information regarding Gigadeuses' lore: It was found resting under Paradigm City in it's current state after the event 40 years ago, it's left arm already found missing it's coverings. It's unknown it was unfinished or something else.
  • This last one, combined with the various allegories to the biblical tree of knowledge, it's connections to The Archetype, and information from episode 14 of the anime imply Gigadeus may very well have been the catalyst of The Event 40 years ago, being discovered after The Archetype was found underground and later was reverse-engineered so that technology evolved "by leaps and bounds" as seen in one of episode 14's newspaper articles. This led to the creation of the Bigs which would later attribute to the cataclysm 40 years ago.
  • Another connection to the biblical Tree Of Knowledge is the Gigadeus' relationship with Angel, whose been deduced by fans as an allegory for the fallen angel/morning star Lucifer: Angel/Lucifer tempted mankind to take from the tree of knowledge, in this case luring Beck to it's power and having him corrupted by it to the point of madness. If Gigadeus was truly reverse-engineered prior to 40 years ago rather than an unfinished creation of humanity, it's possible this too might have involved Angel and Big Venus in some form, which in turn may explain their fall from grace and the loss of their wings since that would further implicate them in the downfall of humanity 40 years ago.
  • The extent of memories Gigadeus possesses goes way further back than 40 years ago, with hints that the history of the world prior to Paradigm City goes all the way back to the era of the dinosaurs, or possibly even earlier. It also possesses information on Angel and Big Venus, as one of the final coherent memories to come from it was a vision of a winged woman resembling Angel. This is further proven in volume 6, when Beck forcefully triggers Angel's wings and pulls her out of Big Fau's pilot seat, seemingly intent on activating Big Venus.
  • Alongside Angel, Beck, and later Roger, it would appear Alex Rosewater may know about Gigadues, as Beck outright stated Alex would never come down to the Gigadeus' lair willingly, and evidently would rather go through the trouble of obtaining Big Fau from the Union rather than use the power of Gigadeus to oppose Big O.


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