Erginus (エルギヌス Eruginusu) is a giant reptilian creature that first appeared in Earth Defense Force 4.1: The Shadow of New Despair. Similar to the enemies Saurous from Global Defence Force and the Vallak from Earth Defense Force 2017, Erginus is a colossal kaiju beast that dwarfs most other enemies in the game and possesses an immense amount of health. Infantry attacks and airstikes are typically useless against Erginus, while Walking Fortress Balam is usually the most effective method of combating it. Erginus returns in Earth Defense Force 5, which also introduces Archelus, another kaiju enemy.
Earth Defense Force 4.1: The Shadow of New Despair
Erginus first appears suddenly near the end of Mission 27: Assault. The same one reappears a couple more times throughout story mode -- in Mission 39: Dozing Beast, where it has fallen asleep in the middle of a city; and Mission 53: Crash (which is supposed to be called Clash, but nevermind), where a Walking Fortress Balam is finally dropped and the creature is finally slain. However, a large group of them as well as a Mutant Erginus appear in Mission 67: Battle of Giants.
In-keeping with 2025 and 4.1's tendency towards being a remake of Global Defence Force, it is similar to the Saurous / Solas monster, with Godzilla-like physical and breath attacks. It is said to have risen from the ocean at some point during the war of 2025, but Ohara later claims that they must have come from outer space, from a planet where they were the apex lifeform: presumably this means they were deployed in the normal Ravager fashion of dumping things in the ocean and letting them walk ashore by themselves. In response to the arrival of the vicious Erginus, the EDF introduced the giant Walking Fortress Balam, which, while not built to take them on specifically, has the necessary equipment to fight them - simple brute force.
A large, mutant Erginus exists, twice the size of any other. Ohara, the Ravager Researcher announces that he believes this to be the actual adult form of the Erginus, and that all others seen before must be juveniles. This one has red skin instead of brown (making it appear quite similar to a Vallak) and its glowing sections now glow yellow instead. As with all mutants, it is much stronger than the regular variety, to the point where Intel urges the Balams to focus on this threat instead of the various other Erginuses remaining.
In its first two appearances, the Erginus proves to be unkillable. Instead the player(s) must survive long enough for it to escape. It appears again, but the EDF drops a Walking Fortress Balam in and player must pilot it and kill the Erginus.
Despite killing this Erginus, several appear at once in one final mission. The player or players are tasked with assisting a large force of NPC Walking Fortress Balams as they battle the Erginuses, protecting the Balams from giant ants, first black and then crimson and finally hornets, followed by another wave of regular ants. The main principle of this mission is that the NPC Balams will attack whatever is closest to them, and can become separated and thus much less effective if too many are fighting bugs instead of Erginuses.
Afterwards, a final Balam is dropped with stats depending on the difficulty level (999,999 health on Inferno, more than any deployable Balam) and a player may pilot this to assist in killing all remaining Erginuses alongside the remaining Balams and then kill the Mutant Erginus. On lower difficulties it is quote possible to ignore the Balam entirely and focus on grabbing pickups until the remaining Balams defeat the mutant, but on higher difficulties there will probably be too few Balams left for this to be left to chance. It is highly advised to stick with the group, as the Balam can be knocked down during its getting up animation, leaving it to constantly take damage without having the time necessary to stand back up. The "charge up" (L3) seems to be designed to prevent this, and appears to work something like the "riposte" move for the Fencer; tapping it at the correct time during a knockdown will result in a much faster recovery.
Erginuses can in turn be kept in a constant knockdown state using the uppercut combo (right, right, left, right) since either of the final two hits connecting will floor even the mutant.
Although the player can kill an Erginus without the Balam, this is not recommended as it will take a significant amount of time to do so. An Erginus on Easy has about one and a half times as much health as a Blue Hector on Inferno. On Inferno, even a basic Erginus will shrug off multiple hits from superweapons like the Tempest S1A, Gungnir or Wild Leviathan.
In DLC 2: Exteme Battle there are multiple fights against Erginuses in maps that do not have a pre-placed Balam, and in one case all enemies are Erginuses which would make it very hard for an Air Raider to earn enough credits to drop one. For these missions, the Erginuses have less health than in the main campaign, making the use of normal high-damage weapons like the Epsilon Armored Railgun tenable.
Perhaps most frightening is the addition of a mutant Erginus to the collection of "red" enemies in DLC 2's mission Bloody River on Inferno difficulty. When the mission already contains Red Drones, Red Flight Vehicles, and a Red Death Queen.
Um, good luck with that.
Erginus has two distinct attack sets, one for dealing with player characters in all normal circumstances, and a second, more powerful set specifically for attacking an NPC or player-controlled Balam.
Notably, Erginus' breath attack is the only one that can hit a character directly underneath it.
Earth Defense Force 5
Erginus returns as an enemy in Earth Defense Force 5. It is effectively identical to its appearance in 4.1, and possesses the same attacks. As in EDF 4.1, there are multiple individuals of the species that appear throughout the game, though initially the EDF is faced with only one.
The EDF attempts to engage Erginus, only to drive it into a combat area where Alpha Team were clearing monsters. Alpha are ordered to fight the monster until an EDF tank unit with infantry support can arrive, but ultimately Erginus flees, completely unfazed despite a prolonged bombardment with tank guns.
However, on cornering the Erginus in a bombed-out city, the EDF deploys a phalanx of EMCs, a specialized heavy vehicle fitted with an atomic ray cannon capable of damaging the monster. While an initial air raid only succeeds in waking the Erginus up, the EMCs succeed in bringing it down. However, they prove ineffectual against the new kaiju Archelus when one of the latter creatures arrives after the Erginus is slain. Gigantic Unloader Barga, a colossal walking machine introduced to combat Archelus, is also employed against Erginus later in the game. Ergnius, at 72 meters in height, is slightly taller than 69 meter-tall Archelus.
The red mutant Erginus never appears in EDF 5 or its DLC packs.
- Erginus is clearly inspired by the popular kaiju Godzilla, reflected by its bipedal upright posture, reptilian dinosaur-like appearance, dorsal plates, and the blue beam attack it fires from its mouth, as well as its tendency to emerge from the ocean and immunity to conventional weaponry. Its triangular curved dorsal plates and elongated head specifically resemble the TriStar Godzilla from the 1998 American remake.
- Erginus also shares some traits with the Kaiju from the more recent American science-fiction film Pacific Rim. Specifically, Erginus is controlled by a malevolent alien force and is deployed from the ocean to attack human civilizations. Erginus also possesses blue bioluminescence on its body, a characteristic of all of the Pacific Rim Kaiju.
- In Earth Defense Force 5, Erginus is often sent into battle backed up by Archelus. This may be a reference to Godzilla's frequent ally Anguirus, upon which Archelus' design is clearly based, as well as the habit of alien invaders in kaiju films to deploy two attacking kaiju at the same time, such as Otachi and Leatherback in Pacific Rim.
- The use of the Walking Fortress Balam and Gigantic Unloader Barga to battle both Erginus and Archelus recalls the trope of utilizing giant mechas to battle giant monsters, as seen in films like Godzilla vs. Mechagodzilla II and Pacific Rim. The Balam and Barga specifically resemble the Jaegers from Pacific Rim.
- In addition to clearly taking inspiration from Godzilla's design, Erginus bears a striking resemblance to the dinosaur genus Therizinosaurus, specifically its elongated neck and incredibly long front claws.
- Erginus is the only kaiju-type enemy in the Earth Defense Force franchise to appear in games set in different continuities.