The Mega-Virus Monsters (the US moniker for the Monsters (怪獣, Kaiju, lit. Strange Beast) are the staple antagonists of Gridman franchise..
They are modeled and materialized in collaboration by the masterminds while primarily created by their human accomplice. Being designed as kaiju-like entities by human pawns of series' main antagonists, they pose an unmistakable threat to Computer World who follow the mastermind's bidding while mirroring the creator's grudging dislikes and malice.
In Denkou Choujin Gridman, the kaiju were created by human accomplice, Takeshi Todo and animated by mastermind, Khan Digifer to do their biddings, more than often acting on the former's petty grudges to the catastrophic extremes that Kahn Digifer intends to have an effect on the human world. The chaos they caused obviously not limited to hack and/or destroy entire city's computer systems, as some cases show them causing affected system to execute functions that normally impossible in normal circumstances, such as creating a dimensional rift or turning a microwave into a bomb which supposedly strong enough to level entire apartment.
In Superhuman Samurai Syber-Squad, the Mega-Virus Monsters are menacing collaborations between Malcolm Frink and Kilokahn. Like the JP counterpart, they are created to topple human civilization and ruining Sam Collins's life by hacking electronics through Computer World, only for Sam to become Servo's host and combat their threat.
Like the previous series above, the kaiju are project creations by Alexis Kerib and Akane Shinjo with the same obedience nature towards its creators. According to Gridman and Anosillus II, they are soulless entities mirroring their creator's purpose into killing those Akane dislikes, all while causing destruction in their path.
In Anti's case, he more sentiment due to his undeniable human-like qualities and his desire to defeat Gridman. After he evolved into Gridknight, Anti becomes more empathetic event towards his kin as he sensed nothing in the erratic Nanashi except Akane's negative feelings from her creative breakdown and depression during sculpting its model. Prior to the series, Akane sculpted a handful of Nanashi prior to Ghoulghilas (not counting her Venoras through which she manages all systems in Tsutsujidai), yet he didn't summon them back to combat Anti and Gridman in Episode 11 - Decisive Battle, arguably due to ill-suited to combat them.
A group of four known as Kaiju Eugenicists has the ability to control kaijus in their disposal, something that Gauma apparently shared despite of them being enemies. To combat the group along with their kaiju army, Gauma utilizes Dynazenon, a robot comprised of four machines where he shared three of them with his new allies.
List of Kaijus/Mega-Viruses
|Denkou Choujin Gridman (JP)||Superhuman Samurai Syber-Squad (US)|
|Imitation Anosillus||Manfu (evil)|
|Jubagon||Unnamed Virus #1|
|Goromaking||Rock n' Roll Virus|
|Devil Phazer||Stupid Virus|
|Akane and Alexis||Other|
|Venora (Akane ver.)||Diriver (by Anti)|
||Anosillus II (independent)|
|Zegga (Akane's kaiju form)|
- Like all various Japanese fictions, the monsters appear as a staple of primary antagonists in various tokusatsu franchise.