Brain


 * "The Brain is now right above us. It is not just a control module - it is a giant fortress and the flagship that leads the massive fleet of Earth Eaters. It is an imposing opponent, but we will destroy the Brain and bring down the Earth Eaters!"
 * —HQ, opening the final assault on the Brain.

The Brain is the final boss of Earth Defense Force 2025 and Earth Defense Force 4.1: The Shadow of New Despair.

As the flagship of the Ravager taskforce in the 2025 invasion, the Brain controls the Earth Eaters. It takes the form of an enormously elongated Earth Eater module, with a large red crystal-like structure at the top which is vulnerable to long-range attacks.

History
Ohara first ponders over the possible existence of the Brain during the mission Machine Squad. When the Earth Eaters arrive, he believes that there are "far too many of them to be working on their own" and that they need a command module of some kind to oversee and direct the invasion. In Monster Party it is stated that investigations are occuring all over the world, and Ohara personally explores several meteor impact sites that fell several days prior to the Earth Eaters' arrival in this mission and Labyrinth of Light.

In City Flaws Ohara confirms the existence of the Brain and relays it to command. However, unable to escape, Ohara is attacked and presumably killed by the Ravagers.

Storm Team joins in with an EDF assault on the Brain, which is hovering over a massive crater, in the mission Fallen Flagship, but the Brain flees before it can be destroyed. After the Ravagers destroy EDF Command Headquarters and a series of backup EDF Command Headquarters sites and the Brain sinks the Eighth Fleet, surviving EDF forces muster and attack the Brain in a desperate final battle, in the mission Star Eaters.

The Tactics Officer advises that Storm Team attack the top of the Brain to destroy it. As the fight continues, a Mothership attempts to break into the combat area to support the Brain. However, personnel in an undamaged part of the destroyed final EDF Command Headquarters site activate a still-surviving secret weapon, the Satellite Blaster, hitting and presumably destroying the Mothership. As the fight continues and all seems lost, Storm Team lead a valiant assault on the Brain, much to the surprise of HQ, who thought everyone had died. Realising that Storm Team are the same legendary group who defeated the Mothership and ended the first invasion of Earth eight years ago, EDF reinforcements arrive: the elite Wing Diver squad Pale Team, Omega Team, and Scout 4, whoever they are.

The Brain is successfully defeated by Storm Team, once again thwarting the Ravagers' invasion of Earth, and humanity cheers the return of the elite squad.

The Brain also appears in the DLC mission Starry Prison, the final mission of DLC3 in 2025 and DLC2 in 4.1. It is not initially present and only appears in the third phase of the mission along with a group of red Earth Eaters. It is referred to as "the Brain" rather than "a Brain," so it is presumably the same craft, though since it is destroyed at the end of the mission it is not particularly clear how or if this fits into the overall timeline.

Gameplay
The Brain on its own is helpless, but it will rely on surrounding Earth Eaters to both attack enemies and provide defense; the sheer number of weapons the Earth Eaters can bring to the battlefield thus make the Brain extremely difficult to defeat.

Earth Eaters can be destroyed quickly by taking down the glowing red core modules, which will destroy all adjacent modules as well. However, like a Deroy with its leg hit locations, destroying the core will prevent item drops from the weapons mounted on the modules that are taken down with it. On higher difficulties it can be necessary to take out a lot of the weapons before the cores, simply to drop enough health items to live through the latter waves.

During mission 77, Fallen Flagship, the Brain will deploy Earth Eaters once it has taken a certain amount of damage, and will then flee the battlefield after taking more damage. During mission 85, Star Eaters, the Brain is fought over three phases, each marked by the appearance of (increasingly more powerful) Earth Eaters.

In Starry Prison the same three phases are encountered, but the first phase has no spawner plates (instead there is a force of Hectors under the low-level Earth Eaters), the second phase spawns Gold Ants and Silver Spiders because the final DLC hates you on a very profound and personal level, and the Brain only actually shows up with the third phase. This level works more like Crazy Skies with the first two Earth Eater deployments; all of their core units must be destroyed to advance the fight, rather than it being based on damage to the Brain as in Star Eaters.

Mission appearances
Main numbers are 2025, 4.1 numbers are in (brackets).
 * Mission 77 (81): Fallen Flagship
 * Mission 85 (89): Star Eaters
 * DLC3 mission 20 (DLC2 mission 23): Starry Prison

Achievements/Trophies
To get this Achievement/Trophy, the player must defeat the Brain a total of six times. Since the Brain can only be destroyed in either Star Eaters or Starry Prison, the player must beat some combination of these two missions six times.

As with all "x Hunter" Achievements/Trophies, the Trophy will unlock immediately upon defeating the required amount of enemies during the mission, rather than on the mission results screen afterwards.