E551 Gigantus

E551 Gigantus is the name of a series of vehicles in the EDF games, first appearing in the original Monster Attack. The Air Raider can call for them in Earth Defense Force 2025 and Earth Defense Force 4.1: The Shadow of New Despair and the level 0 Gigantus is one of the starting items for the class.

The Earth Defence Force: Insect Armageddon equivalent is the Sceptrum III Battletank. In Earth Defense Force 5 it is replaced by the Blacker tank series.

Pre-2025
The Gigantus appears pre-placed on certain maps in games up to and including 2017, with stats that vary according to the difficulty level, and can be used by any class. Unlike its later counterpart, it has infinite ammunition.

Games prior to 2017 used a different design for the Gigantus, while the version in 2017 was very similar to its incarnation in 2025.

In Monster Attack it had the rather unique ability to drive underwater.

Description
The Gigantus is a main battle tank armed only with a single primary cannon; despite there being a coaxial machine gun barrel on the in-game model, no Gigantus has a secondary weapon. It is a fast, manoeuvrable and tough vehicle, but most versions have fairly limited ammunition. As its level increases the Gigantus increases in speed, to the point it is possible to perform manoeuvres like skids that really have no business being done by a tracked vehicle.

Most versions of the Gigantus fire a single powerful explosive shell in a long arc, requiring some compensation for drop at long range. While the rounds deal great damage, the Gigantus is not as powerful as the Epsilon Armored Railgun.

Strategy
The Gigantus is best used for fast hit-and-run attacks that make use of its great speed and fast-turning turret, though it takes some practice to learn to compensate for the arc of its projectile. It is a reasonable general-purpose vehicle but is outshone in most potential applications: the E651 Titan is tougher, the Epsilon Armored Railgun is better for dealing with single targets, the BM03 Vegalta is more flexible, and the Armored Vehicle Grape and Naegling Self-Propelled Rocket Launcher better at dealing with groups. It can still be used effectively if it is equipped with ZE-Guns for taking on weaker enemies, since its low main gun ammunition means the player must make every shot count.

It is easy to access the top of the Gigantus for placing Posts, Vendors, turrets and the like, though it should be remembered that while the turret has no collision box, it does have a hitbox and it is quite possible for turrets to damage the tank if they hit the gun or turret. As with all armored vehicles, placing ZE-Launchers on the Gigantus is one of the more efficient ways of destroying it.

Variants
A number of odd variants of the Gigantus exist, mostly introduced in EDF 4.1's DLC.

The Melt Buster is the main oddity in 2025. This modified close-combat Gigantus is armed with a cannon that effectively fires an Ant's acid spray, doing a fairly impressive amount of damage for its level with its rate of fire and generous capacity taken into account.

The three variants with Custom in their name are "sniper" versions which fire a high-speed, long-range projectile with a flat trajectory and considerably increased recoil. The damage is slightly decreased compared to the nearest standard variant, however.

The Bullet Girls E551 has markings related to the anime of the same name and is armed with a much-weakened version of an E651 Titan's "smooth-bore gun" secondary turret weapon, with the same ability to penetrate multiple targets.

The two DCC-Zero tanks also have anime-related markings and are armed with a weakened version of a BM03 Vegalta Buster Arms' Dispersal Howitzer that fires over twice the number of projectiles.

The EDF2 IfPS variant has markings promoting Earth Defense Force 2: Invaders From Planet Space and an overall color scheme based on that of the classic Gigantus. It is armed with a "Blaster Turret," a weakened version of the Vulture Laser Cannon from the EF24 Bazelart Vulture.

The Natsuiro High School version is armed with a "Deluge Gun," which is essentially a weak version of the Ranger's Super Acid Gun, with the same 60 shots / sec fire rate and arcing trajectory. It is actually a fairly effective weapon at lower difficulty levels, though it quickly becomes obsolete.

All Gigantuses have a crew capacity of 1 and require 2,700 credits to drop. Vehicles marked with (DLC) are exclusive DLC for EDF 4.1.

Trivia

 * The 2017 and 2025 Gigantus is an M1A2 Abrams.
 * NPC Gigantus tanks appear in EDF 4.1, and have armor and firepower scaled to the current difficulty level. They are usually stationary, though some follow fixed routes before stopping, and provide a valuable boost in firepower when they are present, since they have excellent accuracy and infinite ammunition. They are particularly good at dealing with Hectors, to the point that mission 14: Preventing Landfall will beat itself even on Inferno.
 * The name of the series varies depending on translation; it is probably supposed to be Gigantes, after a tribe of 100 offspring of Gaia who waged war on the Gods in Ancient Greek legend. These were the original "giants," though the word did not have its modern meaning and at the time they were generally depicted as human-sized.
 * Gigantus is a Latvian plural accusative form of gigants, and would literally mean "(those things) that are giants." Oddly it is pronounced as if it is German, "gee-gant-us" rather than "jai-gan-tus."
 * The vehicle's weapon would be correctly referred to as a "gun" or "cannon:" a howitzer is a gun designed for high-angle indirect fire, the halfway point between a cannon and a mortar.
 * The Deluge Gun's capacity is specifically noted to be measured in liters.